Reduced Energy Offsets and Low Energy Losses Lead to Efficient (∼10% at 1 sun) Ternary Organic Solar Cells

Autor: María Privado, Rahul Singhal, Fernando Langa, Emilio Palomares, Pilar de la Cruz, Cristina Rodríguez Seco, Ganesh D. Sharma
Rok vydání: 2018
Předmět:
Zdroj: ACS Energy Letters. 3:2418-2424
ISSN: 2380-8195
DOI: 10.1021/acsenergylett.8b01400
Popis: Two organic semiconductor molecules, CS01 and MPU3, an electron donor and electron acceptor, respectively, are described for use in organic bulk heterojunction solar cells. The highest occupied molecular orbital (HOMO) energy offset (ΔEHOMO) between these two molecules is as low as 0.29 eV. Moreover, the lowest unoccupied molecular orbital (LUMO) energy offset (ΔELUMO) is as low as 0.14 eV. Nonetheless, the interfacial charge-transfer process upon light excitation is extremely efficient, and solar cells with efficiencies, under normal conditions, as high as 7.81% have been fabricated. Furthermore, the incorporation of PC71BM (another electron acceptor molecule) to fabricate a triple organic heterojunction led to efficiencies close to 10% at 1 sun irradiation conditions. The improvement is due to a better panchromatic harvesting of the sunlight and a better charge balance, which allows the rapid extraction of carriers before they can recombine.
Databáze: OpenAIRE