Efficient Double- and Triple-Junction Nonfullerene Organic Photovoltaics and Design Guidelines for Optimal Cell Performance

• Published in: ACS energy letters Vol. 5; no. 12; pp. 3692 - 3701
• Main Authors: Firdaus, Yuliar, Ho, Carr Hoi Yi, Lin, Yuanbao, Yengel, Emre, Le Corre, Vincent M, Nugraha, Mohamad I, Yarali, Emre, So, Franky, Anthopoulos, Thomas D
• Format: Journal Article
• Language: English
• Published: American Chemical Society 11.12.2020
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.0c02077

The performance of multijunction devices lags behind single-junction organic photovoltaics (OPVs) mainly because of the lack of suitable subcells. Here, we attempt to address this bottleneck and demonstrate efficient nonfullerene-based multijunction OPVs while at the same time highlighting the remaining challenges. We first demonstrate double-junction OPVs with power conversion efficiency (PCE) of 16.5%. Going a step further, we developed triple-junction OPVs with a PCE of 14.9%, the highest value reported to date for this triple-junction cells. Device simulations suggest that improving the front-cell’s carrier mobility to >5 × 10–4 cm2 V–1 s–1 is needed to boost the efficiency of double- and triple-junction OPVs. Analysis of the efficiency limit of triple-junction devices predicts that PCE values of close to 26% are possible. To achieve this, however, the optical absorption and charge transport within the subcells would need to be optimized. The work is an important step toward next-generation multijunction OPVs.