Owing to the advancement in new material design over the past few years, the power conversion efficiencies (PCE) of polymer solar cells have now reached over 15% and 17% for single-junction and multi-junction devices, respectively. However, in order the meet the commercialization requirement, further improvement in device stability and the exploration of niche applications of polymer solar cells are urgently needed. In this talk, I will discuss how to utilize an integrated strategy combining material design, interface engineering and optical management to tackle the efficiency and stability challenges of polymer solar cells. I will particularly highlight our work on using optical management as a powerful means to enhance the performance of polymer solar cells by maximizing the light harvesting property of the devices. The capability to use optical model to precisely predict the light propagation property and charge generation rate within the devices allows us to design optimal device architectures with improved performance and stability. I will also discuss how to apply high throughput optical model to rapidly screen more than 10 million device structures in order to identify the very best device design for extremely high performance tandem and semitransparent polymer solar cells (ST-PSCs). In addition, I will highlight how to engineer the optical property of ST-PSC for smart greenhouse applications, as well as the design of multiple-function ST-PSC with both heat insulation and power generation properties。