Hetero-structures for Efficient Luminescent Devices

ended

We propose to engineer stable-highly luminescent heterostructures based on defect tolerant benign perovskites and their integration into efficient planar/thin film optoelectronic devices. Primary targeted devices are: blue and white planar electroluminescent devices, high efficiency solar cells and electrically pumped lasers. We will use processing methods that are compatible with large area industrial processes, in particular focusing on vapour deposition using thermal sublimation of the perovskite precursors. The boundaries of this simple, scalable and economic coating method will be determined using an advanced real time in-situ optical monitoring system based on hyperspectral imaging. This tool will unveil the limits and processing conditions for the preparation of uniform and very thin (< 10 nm) crystalline thin-film semiconductors. We will also attempt to replace the toxic lead in today’s most studied perovskite materials, by less toxic materials such as tin and silver/bismuth mixtures. Here vacuum based processing is beneficial in view of the limited air-stability and solubility of their pre-cursor salts. Accurate vapour deposition methods will allow the fabrication of perovskites in multiple layered heterostructures (MLH) that passivate the perovskite crystal boundaries. This will increase their thermal and structural stability and above all their photoluminescence efficiency. With the sophisticated processing control, multiple quantum wells (MQWs) will be engineered. MQWs are promising for light-emitting devices, in particular for lasers. The impact of the project is large on various fields ranging from processes, materials and device engineering, physics, and energy. High efficiency, planar LEDs and solar cells, can shift the energy landscape and strongly help to meet the worlds CO2 reduction targets. The demonstration of electrically pumped lasing in easily processed thin film semiconductors will generate so far un-available fields of science.