Efficiency enhancement of inverted polymer solar cells by doping NaYF4:Yb3+, Er3+ nanocomposites in PCDTBT:PCBM active layer

In this paper, for the first time, a broadband absorption of PSC is realized by combining bifunctional NaYF4:Yb3+, Er3+ nanocrystals exhibiting scattering and UC effect into the active layer. For the NaYF4:Yb3+, Er3+ NCs-doped PSCs, enhancement of the Jsc value for NaYF4:Yb3+, Er3+ NCs is approximately 8.68%, compared to the optimized control PSC. As a result, the mixed NaYF4:Yb3+, Er3+ NCs device shows a high efficiency. For the origin of the enhancement, our theoretical and experimental studies show that the broadband resonance is achieved by the simultaneous excitation of versatile scattering resonances and UC effect.