[PHYS-05]Minimized surface deficiency on wide-bandgap perovskite for efficient indoor photovoltaics

Indoor photovoltaic (IPVs), which are capable of converting low-intensity indoor light (fluorescent lamps, white LED) into electrical power, have become a promising alternative to effectively power the wireless sensors in the future of IoT (Internet of Things) ecosystem. A simple strategy by applying phenethylammonium chloride (PEACl) to reduce the energy loss and suppress the phase segregation of wide-bandgap PVSCs is developed, leading to a merit power conversion efficiency (PCE) of 18.3% under 1 sun illumination, and a PCE of 35.6% under a white light-emitting diode (LED) with an illumination of 1000 lux. Impressively, the device delivers a minimum energy loss of 670 meV, which is among the smallest value reported for perovskite-based indoor photovoltaics. Our results provide the insights in defect passivation for enhancing the performance of wide bandgap PVSCs and exploring their possible applications for future IoT ecosystem.perovskite film are improved, leading to the enhancement of PCE to 12.40% with excellent stability, which is among the highest reported efficiencies.

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[PHYS-03]Low-temperature processed carbon electrode based inorganic perovskite solar cells with enhanced photovoltaic performance and stability

This work provides a facile composition engineering method to improve the performance and stability of carbon-based all-inorganic perovskite solar cells. By simply bromide incorporation, the morphology and crystallinity of perovskite film are improved, leading to the enhancement of PCE to 12.40% with excellent stability, which is among the highest reported efficiencies.

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[ORG-01]A dopant-free polymeric hole-transporting material enabled high fill factor over 81% for highly efficient perovskite solar cells

A dopant-free polymeric hole transport material (HTMs) was synthesized to fabricate the n-i-p type perovskite solar cells (PVSCs). The carbonyl (C=O) groups can passivate defects of under-coordinated Pb atoms exist in the surface of perovskite films. PBT1-C based devices achieve a fill factor (FF) of 81.22%, which is the highest value among the dopant-free polymeric HTMs based PVSCs. A PCE of 19.06% is obtained compared to that of the P3HT based device.

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[MAT-04]Coating two-dimensional MoS2 with polymer creates a corrosive non-uniform interface

Two-dimensional (2D) materials and soft materials are both susceptible to mechanical instabilities, such as buckling, wrinkling, folding and creasing, especially when located on surfaces. Here, we report that weak van der Waals interactions cause the interface between 2D molybdenum disulphide (MoS2) and a soft poly(methyl methacrylate) coating to demonstrate mechanical instability and delamination. The resulting non-uniform and buckled interface greatly hampers the ability of the coating to protect the MoS2 substrate. Also, the corrosion rate of 2D MoS2 and quench rate of intrinsic luminescence in 2D MoS2 were significantly accelerated by the soft coating. Owing to the formation of corrosive cavities at the interface, the geometry and size of the flakes became the dominating factor, and a critical size of 2D flakes for such interfacial instability was determined based on elasticity theory. Such hazardous corrosion in a 2D material caused by a soft coating raises concern for their use in electronic packaging, and for the processing of van der Waals-layered materials for future applications.

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[MAT-03]Interfacial modification through a multifunctional molecule for inorganic perovskite solar cells with over 18% efficiency

One multifunctional molecule 5-Amino-2,4,6-triiodoisophthalic acid (ATPA) was employed as interfacial layer between CsPbI3 and TiO2. The ATPA not only results in cascade energy level alignment, but also interacts strongly with CsPbI3 layer and effectively passivates the defects. The optimized devices based the ATPA modified CsPbI3 deliver a high efficiency of 18.12% with excellent stability.

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[MAT-02]Vertical orientated Dion–Jacobson quasi‐2D perovskite film with improved photovoltaic performance and stability

This work employed NH4SCN additive to facilitate the orientation of perovskite crystal growth to be perpendicular to the substrate and narrowed the layer number distribution to around n = 3 and n = 4. The device derived from the quasi‐2D DJ (BDA)(MA)4Pb5I16 perovskite film processed with NH4SCN shows a PCE of 14.53%, which is among the highest values reported for 2D PVSCs prepared at room temperature. Moreover, the device retains 85% of its initial PCE after 900 h storage in ambient conditions with a humidity level of 50 ± 5%.

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[MAT-01]Dopant‐free crossconjugated hole‐transporting polymers for highly efficient perovskite solar cells

Two isomeric crossconjugated polymer hole-transporting materials (HTMs) are developed to demonstrate significantly distinct device power conversion efficiencies (PCEs) under the same device fabrication conditions, 11.1% PPE1 while 19.3% for PPE2, which is found to be due to the improved quality of perovskite films made on top of PPE2. More excitingly, the PPE2-based perovskite solar cells (PVSCs) can further achieve a more impressive PCE of 21.3% through suitable surface passivation.

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