The global energy demand is increasing at alarming rate as the number of industries increase day by day in our society. The fossil fuels solely cannot be continued to meet such large demands. The use of fossil fuels also causes different environmental hazards. Concerning about the global warming and high price of fossil fuels, development of environmentally clean alternative energy resources has to be explored to meet our urgent demand. One of the promising approaches as an alternative resource is solar energy conversion, i.e., conversion of sunlight to electricity. Recently, we pursue active research mainly in the three key areas: (i) Inorgnic-Organic hybrid solar cells, (ii) Organic solar cells and (iii) Perovskite solar cells.