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

气候变化对人类构成了根本性挑战。仅在加拿大，自1948年以来，平均气温就上升了1.7 °C，接近2 °C的不归点，北部、大草原和北方不列颠哥伦比亚省的气温上升幅度更高。如果采取某些行动，包括从碳经济向清洁能源经济过渡，这种威胁可以减轻。太阳是可再生能源的主要来源，到2050年，太阳能将提供全球能源需求的一半。如果开发新的太阳能收集技术并将其集成到能源系统中，这是可能的。 基于有机-无机卤化物钙钛矿的太阳能电池为低成本和高效率的太阳能提供了平台。钙钛矿是一类可溶液加工的半导体材料，具有良好的光电性能。2019年，太阳能电池的效率达到25.2%，这是有史以来光电池发展最快的一年，它正在接近包括硅在内的一些成熟的光伏平台。 然而，这一惊人的成就被一个关键的挑战所抵消;今天的钙钛矿迅速退化。这对这类有前途的材料提出了关键挑战。由于该领域相对较新，因此注意力一直集中在最大化零时间效率上。但现在最需要的是回答这些紧迫的问题：钙钛矿降解的关键途径是什么，特别是在操作中？钙钛矿能稳定下来吗？什么是具有类似钙钛矿性质但稳定性更好的替代材料？ 该研究计划的主要目标是揭示钙钛矿降解的机制，这些知识将指导我们合成具有更高稳定性和功能的新材料组合物。最稳定的材料将用于开发耐用，低成本的太阳能电池。改变其带隙的最不稳定的材料（即，彩色）当暴露于电偏置等温和的外部条件时，将成为下一代广受欢迎的彩色电子墨水显示器的新平台。最结晶的材料，表现出较长的载流子扩散长度，将用于灵敏的X射线探测器的开发。

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.