Affordable Perovskite Solar Irrigation Systems for Small-holder Farmers in Ethiopia (APSISSFE) Over 85 million Ethiopians depend on rain-fed agriculture. Climate change is increasing vulnerability and poverty amongst small-holder farmers, 21% of whom are female headed. However, women are responsible for about 40% of agricultural activities in Ethiopia. Research by Ethiopian partners in this project shows that the provision of small, solar-powered water pumps to irrigate vegetables and cash crops is a highly effective means of increasing resilience to climate-induced stresses and shocks, enhancing household food security, producing of cash crops, reducing women's labour, and  ultimately enabling escape from the poverty cycle. Unfortunately, such irrigation systems are presently beyond the means of most farmers.  We propose to drop the cost of solar irrigation systems to a level affordable for Ethiopian small-holder farmers by: (i) advancing the science required to increase the performance and stability potential of halide perovskite photovoltaics (PV) cells; (ii) customizing the engineering required by significantly enhancing the efficiency of power electronic motor drive for pumps to the precise requirements of Ethiopian smallholders; and (iii) taking an Inclusive Innovation approach to co-designing the whole system with end-users to ensure that it is locally-appropriate and effectively reduces women's work.  We propose that the lead halide perovskites constitute an ideal emerging solar power technology to enable inclusive manufacture in Ethiopia of community-level solar powered irrigation systems because these materials can be printed at relatively low-cost on lightweight, flexible substrates. Here, we focus on solving critical interface loss and stability issues in perovskite solar cells that currently inhibit their commercial deployment. Concomitant with this, we will enhance the engineering of the irrigation system by developing modular and scalable solar inverters using advanced power electronic technologies and precisely designing the pump for small farms with shallow water tables. The solar powered irrigation system will be deployed in Ethiopia to ensure socio-economic and environmental appropriateness and provide a platform for scaled local engineering of the systems.  This proposal represents an innovative and unique programme of leading-edge experimental science and systems engineering studies, which are of direct relevance to enhancing economic development and welfare in Ethiopia. The interdisciplinary project will explore some of the central structure-composition-property issues of halide perovskite interfaces and their integration into systems, which brings together the complementary expertise of the applicants and will exploit techniques in which the UK is internationally competitive and in many aspects internationally leading. The PI, Co-Is and project partners have strong national and international reputations in their fields and an impressive track record in delivering research of the highest quality. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.