Recent progress in the design of narrow bandgap conjugated polymers for high-efficiency organic solar cells

The critical review on the recent development of novel narrow bandgap polymers for high-efficiency polymer solar cells concentrates on (i) the structural design of narrow bandgap polymers, which occupy a central place in recent advances in high-efficiency polymer solar cells, (ii) the intrinsic physics and chemistry of special properties, such as absorption, bandgap and energy levels, and (iii) the correlation of polymer structure and device fabrication with their photovoltaic performances. The statistical summaries of their device parameters are also discussed. The description of these structure-property correlations may guide the rational design of polymer structures and the reasonable evaluation of their photovoltaic performance.