Novel organic-inorganic perovskites for durable solar cells, sensitive X-ray sensors, and color e-ink displays

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Climate change poses a fundamental challenge to humanity. In Canada alone, the average temperature has warmed by 1.7 °C since 1948, approaching 2 °C non-return point, with even higher temperature increase in the North, the Prairies, and northern British Columbia. This threat can be mitigated if certain actions are taken, including the transition from carbon economy to clean energy economy. The Sun is a major source of renewable energy, and solar energy should provide half of the global energy demand by 2050. This is possible if new solar harvesting technologies are developed and integrated into energy systems. Solar cells based on organic-inorganic halide perovskites provide a platform for low-cost and high-efficiency solar energy. Perovskites are a family of solution-processable semiconductors with promising properties for optoelectronic applications. Perovskite solar cells reached an efficiency of 25.2% in 2019, representing the fastest ever progress of photovoltaics; it is approaching some mature photovoltaic platforms including silicon. However, this stunning achievement is offset by a key challenge; perovskites today degrade rapidly. This poses a key challenge to this otherwise promising class of materials. As the field is relatively novel, attention has been hitherto concentrated on maximizing zero-time efficiency. But what is first and foremost needed now is to answer these pressing questions: What are the key pathways of degradation of perovskites, especially in-operando? Can perovskites be stabilized at all? What are the alternative materials with perovskite-like properties, but better stability? The main objective of this research program is to reveal the mechanisms through which perovskites degrade, knowledge that will guide us to synthesize new material compositions with improved stability and functionalities. The most stable materials will be used to develop durable, low-cost solar cells. The least stable materials, which change their bandgap (i.e., color) when exposed to mild external conditions such as electrical bias, will become a new platform for next-generation, sought-after color e-ink displays. The most crystalline materials, which exhibit long carrier diffusion lengths, will be used for the development of sensitive X-ray detectors.