A molecular photosensitizer achieves a Voc of 1.24V enabling highly efficient and stable dye-sensitized solar cells with copper(II/I)-based electrolyte

To develop photosensitizers with high open-circuit photovoltage (V-oc) is a crucial strategy to enhance the power conversion efficiency (PCE) of co-sensitized solar cells. Here, we show a judiciously tailored organic photosensitizer, coded MS5, featuring the bulky donor N-(2',4'-bis(dodecyloxy)-[1,1'-biphenyl]-4-yl)-2',4'-bis(dodecyloxy)-N-phenyl-[1,1'-biphenyl]-4-amine and the electron acceptor 4-(benzo[c][1,2,5]thiadiazol-4-yl)benzoic acid. Employing MS5 with a copper (II/I) electrolyte enables a dye-sensitized solar cell (DSC) to achieve a strikingly high V-oc of 1.24V, with the V-oc deficit as low as 130mV and an ideality factor of merely 1.08. The co-sensitization of MS5 with the wider spectral-response dye XY1b produces a highly efficient and stable DSC with the PCE of 13.5% under standard AM1.5G, 100mWcm(-2) solar radiation. Remarkably, the co-sensitized solar cell (active area of 2.8cm(2)) presents a record PCE of 34.5% under ambient light, rendering it very attractive as an ambient light harvesting energy source for low power electronics. Designing photo-sensitisers with high open-circuit voltage (V-oc) is desirable to enhance the power conversion efficiency (PCE) of co-sensitized solar cells. Here, the authors employ a judiciously tailored organic sensitiser MS5 with copper electrolyte to achieve a V-oc of 1.24V, and recorded PCE of 34.5% under ambient light.

Automated summary

Developing photosensitizers with high open-circuit voltage (V-oc) is important to improve the power conversion efficiency (PCE) of co-sensitized solar cells. By employing a carefully tailored organic sensitizer MS5 with copper electrolyte, the authors achieved a V-oc of 1.24V and recorded a PCE of 34.5% under ambient light.