A polymer tandem solar cell with 10.6% power conversion efficiency

Abstract

An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap <1.4 eV), poly[2,7-(5,5-bis-(3,7-dimethyloctyl)-5H-dithieno[3,2-b:2′,3′-d]pyran)-alt-4,7-(5,6-difluoro-2,1,3-benzothia diazole)] with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25 °C, 1,000 Wm−2, IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%.

High‐Performance Polymer Solar Cells Based on a Wide‐Bandgap Polymer Containing Pyrrolo[3,4‐f]benzotriazole‐5,7‐dione with a Power Conversion Efficiency of 8.63%

“…Recent progress demonstrated high power conversion efficiencies (PCEs) larger than 10% for both single and multijunction PSCs 2. To access the commercialization, however, further improvement of the PCE is required, which can be achieved by developing efficient polymer donors for BHJ active layer materials.…”

Significant Stability Enhancement in High‐Efficiency Polymer:Fullerene Bulk Heterojunction Solar Cells by Blocking Ultraviolet Photons from Solar Light

“…The power conversion efficiency (PCE) of organic solar cells has been noticeably improved up to 8%–10% for single‐stack devices and 11.5% for tandem devices,7, 8, 9, 10, 11, 12, 13, 14, 15, 16 since early works for the bulk heterojunction (BHJ) concept and the BHJ nanomorphology control 17, 18, 19, 20, 21, 22, 23, 24, 25. Interestingly, most of the high‐efficiency (>8%) organic solar cells are fabricated with blends of conjugated polymers and soluble fullerenes, the so‐called polymer:fullerene solar cells, because fullerene derivatives possess desirable energy band structures and high electron mobilities 26, 27, 28…”

New generation solar cells: concepts, trends and perspectives

“…5), presenting complementary absorption spectra, were stacked under optimized thicknesses, and an outstanding V OC of 2.28 V was observed, yielding an excellent PCE of 11.5%, which exceeds the record efficiency of a double-junction device. 40 Interestingly, it has been suggested previously that triple-junction tandem solar cells tend to achieve higher V OC compared to their double-junction analogues. 43 Alternatively, very powerful tandem devices have also been prepared using small molecule active materials.…”

“…18 In terms of materials, a number of polymers, such as PPV-based, 19 P3HT 29 and PTB7 31 set important milestones on the way to today's state-of-the-art in electron-donor structures. Lately, a new polymer, PDTP-DFBT, 40 as well as polythiophene SMPV1, 54 have established new landmarks, by overcoming the 10% efficiency threshold, in tandemmode devices. As regards electron acceptors, the most important development consists of fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) 22,23 which has been the most successful and widely used analogue.…”