Simultaneously improving efficiency and transparency of semitransparent organic solar cells by constructing semitransparent microcavity

Semitransparent microcavity is constructed by sandwiching an active layer between the WO3/Ag/WO3 multilayer electrode and the thin Ag electrode capped by one-dimensional photonic crystals (1DPCs) to simultaneously improve light absorption and transmission of the semitransparent organic solar cells (OSCs). Optical simulations demonstrate that the upper limit to power conversion efficiency (PCEmax) of the semitransparent OSCs is improved up to 8.37%, an improvement of 14.0% from that of the conventional device without the microcavity; simultaneously, the transparency of the device reaches a relatively high value of 21.7% with an improvement of 8.0%. In addition, it is revealed that PCEmax, transparency and see-through color of the devices bear strong relevance to the photonic bandgap of 1DPCs. Transparency for the semitransparent OSCs can be tuned from 2.4% to 33% and the see-through color of the semitransparent OSCs can be tuned in a broad range by tailoring the center wavelength of the photonic bandgap. Results from the paper demonstrate the semitransparent microcavity is an efficient light trapping structure for semitransparent OSCs and can find application in the design and fabrication of semitransparent OSCs with high efficiency and high transparency.