| 초록 |
Interfacial layer of organic solar cells (OSCs) in cascade structures could have higher charge transfer (CT) state energy, minimizing exciton recombination at the donor-acceptor interface and hence increasing internal quantum efficiency (IQE).1, 2 We report enhanced IQE and absorption of parallel-like bulk heterojunction (BHJ) OSCs in broad spectral regions by inserting multi-functional layers (MFL).3 The inserted MFL has an energy level between main donor and acceptor levels, assisting the exciton dissociation of the CT state. Furthermore, two donors have complementary absorption spectra, yielding higher and broader absorption efficiency. When a ClAlPc:C60 layer was inserted as an MFL on top of CuPc:C60, the short circuit current (Jsc) was improved from 10.35 mA/cm2 to 11.62 mA/cm2, leading to an increase of the PCE from 2.34 % to 2.71 %. In addition, when a ClAlPc layer was inserted as an MFL between CuPc and C60 in a bilayer OSC, the PCE was enhanced from 1.33 % to 1.69 %. |
