ALL PAST & FUTURE EVENTS AS WELL AS MASTERCLASSES WITH A SINGLE ANNUAL PASS
The Future of Photovoltaics: Organic, Perovskites, CIGS, Tandem
24-25 January 2024
2pm-8pm
Berlin Time
Online Event
We examine the latest technical and commercial development trends in perovskite, organic, tandem, CIGS and other next-gen photovoltaic technologies. The conference is a balanced blend of discussions on manufacturing, research and R&D as well as start-up innovations. It aims to bring together all key players from researchers to start ups to manufacturing companies. It covers all aspects including manfuacturing, stability, performance, novel materials, promising production methods such as printed or R2R, new form factors, novel applications beyond utility. The scope of the event is very international with a speaker programme curated and handpicked by the TechBlick team. If you wish to present in the programme please contact khasha@TechBlick.com
More events on the topic:
The Future of Photovoltaics 2021
The Future of Photovoltaics 2022
Some of the confirmed speakers thus far include Kaust, American Perovskites LLC, InterPhases Solar, Empa, University of Colorado Boulder, Greatcell Energy, Perotech, n-ink, University of Stuttgart, Solaires Entreprises, University of Manchester, North Carolina State University, Taiwan Perovskite Solar Corp, Oxford Suzhou Centre for Advanced Research, Ribes Tech, Verico Technology, Verde Technologies Inc, Caelux, Epishine etc
Perovskites | Organics | CIGS | Tandem | R2R | Inkjet | Printed | Thin Film Deposition | Scale-Up | Stability | Thin Film Barriers | Material Innovations | Substrates | Lead-Free | AI and Machine Learning | Commercialization
Full Agenda
The times below is Central European Times (CET).
Coming Soon
24 January 2024
TechBlick
Wednesday
Welcome & Introduction
More Details
1:00 PM
Khasha Ghaffarzadeh
Welcome & Introduction
1:00 PM
24 January 2024
KAUST
Wednesday
Pathways to Efficient and Stable Perovskite/Silicon Tandem Solar Cells
More Details
1:25 PM
Stefaan De Wolf
Professor
In this presentation I will discuss the multiple ways how monolithic perovskite/silicon can be fabricated, built from textured silicon heterojunction solar cells, with an emphasis on solution of the perovskite top cell. Bulk and contact passivation of the perovskite are instrumental to obtain a high performance, which can be obtained through molecular additive engineering. Combined, this recently led to a certified power conversion efficiency of 33.7% for a monolithic perovskite/silicon tandem solar cell. This will be followed by a discussion about the outdoor performance of such tandems and the need for robust and perovskite-compatible encapsulation to do so. I will then move on to discuss reliability aspects of such tandems under accelerated degradation tests such as damp-heat testing, reverse-bias and potential induced degradation, as well as possible mechanical failure due to top-contact delamination. I will conclude my talk with arguing how bifacial perovskite/silicon tandems aid in improved performance as well as stability.
Pathways to Efficient and Stable Perovskite/Silicon Tandem Solar Cells
1:25 PM
In this presentation I will discuss the multiple ways how monolithic perovskite/silicon can be fabricated, built from textured silicon heterojunction solar cells, with an emphasis on solution of the perovskite top cell. Bulk and contact passivation of the perovskite are instrumental to obtain a high performance, which can be obtained through molecular additive engineering. Combined, this recently led to a certified power conversion efficiency of 33.7% for a monolithic perovskite/silicon tandem solar cell. This will be followed by a discussion about the outdoor performance of such tandems and the need for robust and perovskite-compatible encapsulation to do so. I will then move on to discuss reliability aspects of such tandems under accelerated degradation tests such as damp-heat testing, reverse-bias and potential induced degradation, as well as possible mechanical failure due to top-contact delamination. I will conclude my talk with arguing how bifacial perovskite/silicon tandems aid in improved performance as well as stability.
24 January 2024
Empa-Swiss Federal Laboratories for Materials Science and Technology
Wednesday
Recent Progress & Key Challenges in Upscaling Flexible All-Perovskite Tandem Mini-module
More Details
1:45 PM
Recent Progress & Key Challenges in Upscaling Flexible All-Perovskite Tandem Mini-module
1:45 PM
24 January 2024
Networking
Wednesday
Meet The Speakers/Networking Break
More Details
2:05 PM
Meet The Speakers/Networking Break
2:05 PM
24 January 2024
Eurecat
Wednesday
InMold Organic Photovoltaics
More Details
2:40 PM
Ignasi Burgues
Research Scientist
For the consolidation of organic photovoltaics (OPV), it is crucial to create market pull through the identification and target of strategic niches, where this technology can exploit its fundamental differentiators.1 For instance, materials engineering has enabled wavelength-selective harvesting with transparent OPV for power-generating windows2 and building-integrated photovoltaics.3 Therein, a simultaneous high efficiency and high transparency are needed. While the community has made relevant developments to maximize the optoelectronic properties of OPV devices, little attention has been paid to their structural properties. High-volume manufacturing technologies such as plastic thermoforming and injection moulding can help expand the opportunities, the capabilities, and the seamless integration of OPV.
In this work we demonstrate, for the first time, the feasibility of fabricating OPV cells and modules embedded into structural plastic parts through injection moulding. This process yields lightweight OPV devices with enhanced device robustness and durability, thanks to the hermetical and conformable encapsulation resulting from the plastic injection. We discuss the interplay between the plastic processing conditions and the OPV device performance and stability, as well as highlight relevant optomechanical and physico-chemical material properties, including recyclable thermoplastic polymeric materials that might facilitate material reuse. Finally, we also show how plastic processing can be used to fabricate low-cost, three‑level hierarchically organized micro/nanometric surface textures that provide additional functionalities, such as light management or self-cleaning.4
InMold Organic Photovoltaics
2:40 PM
For the consolidation of organic photovoltaics (OPV), it is crucial to create market pull through the identification and target of strategic niches, where this technology can exploit its fundamental differentiators.1 For instance, materials engineering has enabled wavelength-selective harvesting with transparent OPV for power-generating windows2 and building-integrated photovoltaics.3 Therein, a simultaneous high efficiency and high transparency are needed. While the community has made relevant developments to maximize the optoelectronic properties of OPV devices, little attention has been paid to their structural properties. High-volume manufacturing technologies such as plastic thermoforming and injection moulding can help expand the opportunities, the capabilities, and the seamless integration of OPV.
In this work we demonstrate, for the first time, the feasibility of fabricating OPV cells and modules embedded into structural plastic parts through injection moulding. This process yields lightweight OPV devices with enhanced device robustness and durability, thanks to the hermetical and conformable encapsulation resulting from the plastic injection. We discuss the interplay between the plastic processing conditions and the OPV device performance and stability, as well as highlight relevant optomechanical and physico-chemical material properties, including recyclable thermoplastic polymeric materials that might facilitate material reuse. Finally, we also show how plastic processing can be used to fabricate low-cost, three‑level hierarchically organized micro/nanometric surface textures that provide additional functionalities, such as light management or self-cleaning.4
24 January 2024
Networking
Wednesday
Meet The Speakers/Networking Break
More Details
3:40 PM
Meet The Speakers/Networking Break
3:40 PM
24 January 2024
American Perovskites
Wednesday
Sunproofing America - Revolutionizing the supply chain for solar cells
More Details
5:15 PM
Nick Denegre
Co-Founder
An early-stage startup company aiming to supply material and equipment for perovskite-based solar technology with production facilities in Colorado. We are driven by a passion for scientific innovation and a commitment to making a positive impact on the world. Our journey began with a simple but powerful idea: to harness the potential of perovskite materials, accelerate the manufacturing of solar cell semiconductors, and create a diversified and inclusive future workforce.
What is a perovskite solar cell?
Perovskite solar cells (PSCs) were developed about 15 years ago and can achieve higher power conversion efficiencies at lower cost compared to traditional solar cells.
What is the hole transport layer?
Hole transport layers (HTLs) are thin films placed in perovskite solar cells to facilitate the efficient movement of positive charges (holes) from the light-absorbing perovskite layer to the electrode.
Why polymer hole transport materials?
AP's polymer hole transport materials (PHTMs) offer advantages such as high hole mobility, thermal and chemical stability, excellent surface contact and passivation, and cost competitiveness, making them desirable for use as HTLs in perovskite solar cells to enhance their performance and stability.
Sunproofing America - Revolutionizing the supply chain for solar cells
5:15 PM
An early-stage startup company aiming to supply material and equipment for perovskite-based solar technology with production facilities in Colorado. We are driven by a passion for scientific innovation and a commitment to making a positive impact on the world. Our journey began with a simple but powerful idea: to harness the potential of perovskite materials, accelerate the manufacturing of solar cell semiconductors, and create a diversified and inclusive future workforce.
What is a perovskite solar cell?
Perovskite solar cells (PSCs) were developed about 15 years ago and can achieve higher power conversion efficiencies at lower cost compared to traditional solar cells.
What is the hole transport layer?
Hole transport layers (HTLs) are thin films placed in perovskite solar cells to facilitate the efficient movement of positive charges (holes) from the light-absorbing perovskite layer to the electrode.
Why polymer hole transport materials?
AP's polymer hole transport materials (PHTMs) offer advantages such as high hole mobility, thermal and chemical stability, excellent surface contact and passivation, and cost competitiveness, making them desirable for use as HTLs in perovskite solar cells to enhance their performance and stability.
24 January 2024
Networking
Wednesday
Meet The Speakers/Networking Break
More Details
5:35 PM
Meet The Speakers/Networking Break
5:35 PM
24 January 2024
University of Manchester
Wednesday
Scalable Semi-transparent Organic Photovoltaics
More Details
6:10 PM
Dr. Emma Spooner
Research Associate
Organic photovoltaics (OPVs) are an emerging thin film solar technology based on organic semiconductors. OPVs are promising due to their potential for solution processability, low temperature manufacture, and tuneable absorption. The latter of these allows for semi-transparent OPVs (STOPVs), meaning visible light can be transmitted whilst electricity is still generated. STOPVs have huge potential for building integrated PV, power generating windows, and other architectural and industrial applications.
Here we will discuss our project based on scalable STOPVs, as part of a collaboration between the University of Manchester and Manchester based company Contra Vision. Work so far includes preliminary transfer-matrix modelling work evaluating different active layer components and top electrodes; dilute donor compositions for tuning light utilisation efficiency; and exploration of a variety of charge transport layers towards a fully printed OPV stack.
Scalable Semi-transparent Organic Photovoltaics
6:10 PM
Organic photovoltaics (OPVs) are an emerging thin film solar technology based on organic semiconductors. OPVs are promising due to their potential for solution processability, low temperature manufacture, and tuneable absorption. The latter of these allows for semi-transparent OPVs (STOPVs), meaning visible light can be transmitted whilst electricity is still generated. STOPVs have huge potential for building integrated PV, power generating windows, and other architectural and industrial applications.
Here we will discuss our project based on scalable STOPVs, as part of a collaboration between the University of Manchester and Manchester based company Contra Vision. Work so far includes preliminary transfer-matrix modelling work evaluating different active layer components and top electrodes; dilute donor compositions for tuning light utilisation efficiency; and exploration of a variety of charge transport layers towards a fully printed OPV stack.
24 January 2024
Brilliant Matters
Wednesday
Materials Developments for Stable, Scalable and Efficient Organic Solar cells
More Details
6:50 PM
Philippe Berrouard
Founder & CTO
Organic photovoltaic technologies are a 3rd generation solar technology which has been steadily improving in the past decade due to rapid evolutions in materials design, device stacks and processing strategies. Due to their high efficiency, non-toxic nature and low-cost-high-volume manufacturing potential, several market-ready applications are now emerging for this technology. For instance, photovoltaic modules for indoor energy harvesting, for integration into buildings such as greenhouses, office buildings or even vehicles. In this presentation Brilliant Matters will outline some of the current challenges in the field of high performance and scalable OPVs from a materials chemistry perspective and will discuss novel materials systems for efficient, stable and scalable OPV devices
Materials Developments for Stable, Scalable and Efficient Organic Solar cells
6:50 PM
Organic photovoltaic technologies are a 3rd generation solar technology which has been steadily improving in the past decade due to rapid evolutions in materials design, device stacks and processing strategies. Due to their high efficiency, non-toxic nature and low-cost-high-volume manufacturing potential, several market-ready applications are now emerging for this technology. For instance, photovoltaic modules for indoor energy harvesting, for integration into buildings such as greenhouses, office buildings or even vehicles. In this presentation Brilliant Matters will outline some of the current challenges in the field of high performance and scalable OPVs from a materials chemistry perspective and will discuss novel materials systems for efficient, stable and scalable OPV devices
25 January 2024
TechBlick
Thursday
Welcome & Introduction
More Details
1:00 PM
Khasha Ghaffarzadeh
Welcome & Introduction
1:00 PM
25 January 2024
Taiwan Perovskite Solar Corp
Thursday
Large-scale perovskite production: materials, processes, and challenges
More Details
1:05 PM
Chih-Hsuan Chao
Research And Development Engineer
In the field of solar energy, it has become a common belief that perovskite solar cells
are advancing at an unprecedented pace. While the historical trajectory may seem
astonishing, we can gain insight by examining the development path of the solar cell
industry, which has progressed from silicon and CIGS (copper indium gallium
selenide) to organic solar cells. Perovskite solar cells represent the culmination of
decades of knowledge and research.
A perovskite solar cell is composed of multiple layers. Each layer is carefully
deposited on a substrate, which imposes certain limitations on the choice of
materials and manufacturing processes for the top layer. To overcome these
limitations, various process technologies such as slot-die coating, blade-coating, and
spray deposition have been developed and refined for large-scale production.
Additionally, a wide range of materials has been extensively studied.
In the presentation, we will delve into the critical considerations for selecting
materials and processes when fabricating perovskite solar cells. Furthermore, we will
highlight the challenges and obstacles associated with these technologies.
Large-scale perovskite production: materials, processes, and challenges
1:05 PM
In the field of solar energy, it has become a common belief that perovskite solar cells
are advancing at an unprecedented pace. While the historical trajectory may seem
astonishing, we can gain insight by examining the development path of the solar cell
industry, which has progressed from silicon and CIGS (copper indium gallium
selenide) to organic solar cells. Perovskite solar cells represent the culmination of
decades of knowledge and research.
A perovskite solar cell is composed of multiple layers. Each layer is carefully
deposited on a substrate, which imposes certain limitations on the choice of
materials and manufacturing processes for the top layer. To overcome these
limitations, various process technologies such as slot-die coating, blade-coating, and
spray deposition have been developed and refined for large-scale production.
Additionally, a wide range of materials has been extensively studied.
In the presentation, we will delve into the critical considerations for selecting
materials and processes when fabricating perovskite solar cells. Furthermore, we will
highlight the challenges and obstacles associated with these technologies.
25 January 2024
Oxford Suzhou Centre for Advanced Research
Thursday
Efficient and Stable Inverted Perovskite Solar Cell with modified Al as a Cathode
More Details
1:25 PM
Dr. Jingsong Huang
Co-Principal Investigator
Inexpensive metal Al is scarcely utilized as the cathode in the perovskite solar cells (PVSCs) because its violent reaction with perovskite active layer results in poor device stability in air. A novel solution-processed cathode interlayer material, surfactant encapsulated polyoxometalate complex [(C8H17)4N]4[SiW12O40] (TOASiW12) is employed to modify Al as the cathode. The power conversion efficiency (PCE) of 20.64% has been achieved in the inverted PVSCs. The findings demonstrate that a thin TOASiW12 layer can effectively obstruct the chemical reaction between Al and perovskite layer, and significantly enhance the device stability. The unencapsulated devices with TOASiW12-modified Al retain more than 80% of the initial PCE after 350 h storage in the ambient atmosphere at 45% relative humidity. This work provides an alternative cathode interlayer material for efficient and stable inverted PVSCs.
Efficient and Stable Inverted Perovskite Solar Cell with modified Al as a Cathode
1:25 PM
Inexpensive metal Al is scarcely utilized as the cathode in the perovskite solar cells (PVSCs) because its violent reaction with perovskite active layer results in poor device stability in air. A novel solution-processed cathode interlayer material, surfactant encapsulated polyoxometalate complex [(C8H17)4N]4[SiW12O40] (TOASiW12) is employed to modify Al as the cathode. The power conversion efficiency (PCE) of 20.64% has been achieved in the inverted PVSCs. The findings demonstrate that a thin TOASiW12 layer can effectively obstruct the chemical reaction between Al and perovskite layer, and significantly enhance the device stability. The unencapsulated devices with TOASiW12-modified Al retain more than 80% of the initial PCE after 350 h storage in the ambient atmosphere at 45% relative humidity. This work provides an alternative cathode interlayer material for efficient and stable inverted PVSCs.
25 January 2024
Toray Research Center
Thursday
Analysis method proposal toward the high-efficiency Perovskite solar cells
More Details
1:45 PM
Tsukasa Koyama
We have provided analytical services and R&D support to customers using innovative analytical techniques and physical analyses for over 40 years, and we have been involved in Perovskite Solar Cells for over 10 years. We will introduce the latest analytical technologies for Perovskite Solar Cells, for example, crystal structure evaluation in the cells by XRD and 4D-STEM, electrical characteristics of the power generation layer for the cells by SSRM and SEM, evolved gas analysis during sample heating by TPD-MS, and depth profile analysis of element and organic molecules distribution by SIMS, etc. Please learn more about our technical information at the presentation
Analysis method proposal toward the high-efficiency Perovskite solar cells
1:45 PM
We have provided analytical services and R&D support to customers using innovative analytical techniques and physical analyses for over 40 years, and we have been involved in Perovskite Solar Cells for over 10 years. We will introduce the latest analytical technologies for Perovskite Solar Cells, for example, crystal structure evaluation in the cells by XRD and 4D-STEM, electrical characteristics of the power generation layer for the cells by SSRM and SEM, evolved gas analysis during sample heating by TPD-MS, and depth profile analysis of element and organic molecules distribution by SIMS, etc. Please learn more about our technical information at the presentation
25 January 2024
Networking
Thursday
Meet The Speakers/Networking Break
More Details
2:05 PM
Meet The Speakers/Networking Break
2:05 PM
25 January 2024
Networking
Thursday
Meet The Speakers/Networking Break
More Details
3:40 PM
Meet The Speakers/Networking Break
3:40 PM
25 January 2024
InterPhases Solar
Thursday
Versatile in-line Roll-to-roll Process for Flexible, Thin-Film Devices
More Details
4:35 PM
Shalini Menezes
Founder, CEO, R&D Director
Fabricating devices with non-vacuum roll-to-roll processes that intrinsically host nano-scale pn junctions offer an attractive platform to create low-cost, flexible, lightweight opto-electronic devices. Incumbent 3G nano technologies still face significant challenges in-terms of stability, toxicity, up-scaling and reproducibility to reach the status of the established technology. Here we present an alternate path that integrates new device structure, process and manufacturing. It features a compact, practical, atmospheric process to manufacture high quality, ordered 3D
nanocrystalline pn homojunction (NHJ) device structures. Exemplified here by two Cu-In-Se (CISe) compounds, the method entails single-step electrodeposition of interconnected network of p-CISe and n-CISe nanocrystals to create a depleted NHJ thin film. Extraordinary attributes the CISe NHJs include non-linear emissions, large carrier mobility, low trap-state-density, long carrier lifetime and likely up-conversion. The NHJ film can be inserted between two electrodes to produce an isotropic device, wherein current can flow in either direction to convert light into electricity or applied voltage into light.
Although originally conceived for CISe solar cells, this radical concept could create NHJs with most II-VI or III-V semiconductors for wide spectrum of applications, e.g., PV panels, LEDs, photodetectors, photoelectrodes, laser diodes, displays, MEMS and optical fibers. Importantly, the NHJ structure can be continuously roll-to-roll processed in ambient atmosphere from aqueous solution. Overall, this approach offers a promising low-cost processing platform to create high performance, stable and scalable devices. The NHJs could essentially perform like 2D planar pn
junctions or artificially ordered 3D nano-structures, but without their high cost and fabrication complexities.
Versatile in-line Roll-to-roll Process for Flexible, Thin-Film Devices
4:35 PM
Fabricating devices with non-vacuum roll-to-roll processes that intrinsically host nano-scale pn junctions offer an attractive platform to create low-cost, flexible, lightweight opto-electronic devices. Incumbent 3G nano technologies still face significant challenges in-terms of stability, toxicity, up-scaling and reproducibility to reach the status of the established technology. Here we present an alternate path that integrates new device structure, process and manufacturing. It features a compact, practical, atmospheric process to manufacture high quality, ordered 3D
nanocrystalline pn homojunction (NHJ) device structures. Exemplified here by two Cu-In-Se (CISe) compounds, the method entails single-step electrodeposition of interconnected network of p-CISe and n-CISe nanocrystals to create a depleted NHJ thin film. Extraordinary attributes the CISe NHJs include non-linear emissions, large carrier mobility, low trap-state-density, long carrier lifetime and likely up-conversion. The NHJ film can be inserted between two electrodes to produce an isotropic device, wherein current can flow in either direction to convert light into electricity or applied voltage into light.
Although originally conceived for CISe solar cells, this radical concept could create NHJs with most II-VI or III-V semiconductors for wide spectrum of applications, e.g., PV panels, LEDs, photodetectors, photoelectrodes, laser diodes, displays, MEMS and optical fibers. Importantly, the NHJ structure can be continuously roll-to-roll processed in ambient atmosphere from aqueous solution. Overall, this approach offers a promising low-cost processing platform to create high performance, stable and scalable devices. The NHJs could essentially perform like 2D planar pn
junctions or artificially ordered 3D nano-structures, but without their high cost and fabrication complexities.
25 January 2024
Verde Technologies Inc
Thursday
Speeding commercialization through early engagement with contract manufacturers.
More Details
true
5:15 PM
Speeding commercialization through early engagement with contract manufacturers.
5:15 PM
Key considerations for startups working with contract manufacturers and how to get the most out of the relationship to accelerate product development and commercialization. Examples from roll to roll contract coating for perovskite photovoltaic.
25 January 2024
Verico Technology Holdings Inc
Thursday
Speeding commercialization through early engagement with contract manufacturers.
More Details
true
5:15 PM
Speeding commercialization through early engagement with contract manufacturers.
5:15 PM
25 January 2024
Networking
Thursday
Meet The Speakers/Networking Break
More Details
5:35 PM
Meet The Speakers/Networking Break
5:35 PM
25 January 2024
Helmholtz-Zentrum Berlin
Thursday
Highly Efficient Monolithic Tandem Solar Cells with Metal-Halide Perovskites
More Details
6:10 PM
Eike Köhnen
Integrating metal halide perovskite top cells with bottom cells formed by crystalline silicon or low band gap perovskites into monolithic tandem devices has recently attracted increased attention due to the high efficiency potential and application relevance of these cell architectures. Here we present our recent results on monolithic tandem combinations of perovskite top-cells with crystalline silicon, and Sn-Pb perovskites as well as tandem relevant aspects of perovskite single junction solar cells.
In 2020, we have shown that self-assembled monolayers (SAM) could be implemented as appropriate hole selective contacts. The implementation of new generation SAM molecules enabled further reduction of non-radiative recombination losses with high open circuit voltages and fill factor. By fine-tuning the SAM molecular structure even further, the photostability of perovskite composition with tandem-ideal band gaps of 1.68 eV could be enhanced by reduction of defect density and fast hole extraction. That enabled a certified efficiency for perovskite/silicon tandems at 29.15%.
By optical optimizations, we could further improve this value to 29.80% in 2021. Periodic nanotextures were used that show a reduction in reflection losses in comparison to planar tandems, with the new devices being less sensitive to deviations from optimum layer thicknesses. The nanotextures also enable a greatly increased fabrication yield from 50% to 95%. Moreover, the open-circuit voltage is improved by 15 mV due to the enhanced optoelectronic properties of the perovskite top cell on top of the nanotexture.
In the end of 2022, we enabled a new world record for perovskite/silicon tandem solar cells at 32.5% efficiency. We demonstrated that an additional surface treatment strongly reduces interface recombination and improves the band alignment with the C60 electron transporting material. With these modifications, single junction solar cells show high open circuit voltages of up to 1.28 V in a p-i-n configuration, and we achieve 2.00 V in monolithic tandem solar cells. A comparable surface treatment was also applied to 1.80 eV band gap perovskites to enable Voc values of 1.35 V and these were integrated into monolithic all-perovskite tandem solar cells enabling a certified efficiency of 27.5%.
In addition to the experimental material and device development, also main scientific and technological challenges and empirical efficiency limits as well as advanced analysis methods will be discussed for perovskite based tandem solar cells. In addition, results on upscaling and stability of these industrial relevant tandem solar cells by thermal evaporation will be shown.
Highly Efficient Monolithic Tandem Solar Cells with Metal-Halide Perovskites
6:10 PM
Integrating metal halide perovskite top cells with bottom cells formed by crystalline silicon or low band gap perovskites into monolithic tandem devices has recently attracted increased attention due to the high efficiency potential and application relevance of these cell architectures. Here we present our recent results on monolithic tandem combinations of perovskite top-cells with crystalline silicon, and Sn-Pb perovskites as well as tandem relevant aspects of perovskite single junction solar cells.
In 2020, we have shown that self-assembled monolayers (SAM) could be implemented as appropriate hole selective contacts. The implementation of new generation SAM molecules enabled further reduction of non-radiative recombination losses with high open circuit voltages and fill factor. By fine-tuning the SAM molecular structure even further, the photostability of perovskite composition with tandem-ideal band gaps of 1.68 eV could be enhanced by reduction of defect density and fast hole extraction. That enabled a certified efficiency for perovskite/silicon tandems at 29.15%.
By optical optimizations, we could further improve this value to 29.80% in 2021. Periodic nanotextures were used that show a reduction in reflection losses in comparison to planar tandems, with the new devices being less sensitive to deviations from optimum layer thicknesses. The nanotextures also enable a greatly increased fabrication yield from 50% to 95%. Moreover, the open-circuit voltage is improved by 15 mV due to the enhanced optoelectronic properties of the perovskite top cell on top of the nanotexture.
In the end of 2022, we enabled a new world record for perovskite/silicon tandem solar cells at 32.5% efficiency. We demonstrated that an additional surface treatment strongly reduces interface recombination and improves the band alignment with the C60 electron transporting material. With these modifications, single junction solar cells show high open circuit voltages of up to 1.28 V in a p-i-n configuration, and we achieve 2.00 V in monolithic tandem solar cells. A comparable surface treatment was also applied to 1.80 eV band gap perovskites to enable Voc values of 1.35 V and these were integrated into monolithic all-perovskite tandem solar cells enabling a certified efficiency of 27.5%.
In addition to the experimental material and device development, also main scientific and technological challenges and empirical efficiency limits as well as advanced analysis methods will be discussed for perovskite based tandem solar cells. In addition, results on upscaling and stability of these industrial relevant tandem solar cells by thermal evaporation will be shown.