Charge Transfer Dynamics and Device Performance of Environmentally Friendly Processed Nonfullerene Organic Solar CellsShow others and affiliations
2018 (English)In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 1, no 9, p. 4776-4785Article in journal (Refereed) Published
Abstract [en]
In the last years, one of the pursuits has been to replace the use of halogenated solvent during the processing of organic photovoltaic (OPV) devices. Herein, we investigate the nonhalogenated solvent, o-methylanisole (o-MA) and the well stabilized o-dichlorobenzene (o-DCB) to process the bulk heterojunction (BHJ) based on PTB7-Th donor (D) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2,3 - d]-s-indaceno [1,2-b:5,6-b] dithiophene) (ITIC) acceptor (A). The formation of D A interfaces with different (solvent-dependent) characteristics was verified by steady-state photoluminescence and morphological and electrical measurements. These measurements show a rather comparable device efficiency of the PTB7-th:ITIC BHJ processed by o-MA (compared to the device processed using o-DCB) despite the lower absorption of the films and the lower V-OC. Also, the charge-transfer (CT) state formation was investigated and the reasons behind the V-OC losses were correlated to the interface variations when processed by different solvents. Some experimental results are then discussed in light of the electronic structure of the molecules calculated using the density functional theory (DFT) method. The comparison between the experimental data and the theoretical calculations give some insights about the microscopic processes involved in the variation of the devices properties processed using the o-DCB and o-Ma solvents. We concluded that the D-A distance clearly affects the CT state energy and consequently the V-OC. Furthermore, higher air stability is observed when the active layer is processed using o-MA instead of o-DCB. The better stability was observed in self-lifetime measurements and air-processed devices.
Place, publisher, year, edition, pages
AMER CHEMICAL SOC , 2018. Vol. 1, no 9, p. 4776-4785
Keywords [en]
green solvents; nonfullerene solar cells; voltage losses; charge transfer state; density functional theory; air stability
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:liu:diva-176038DOI: 10.1021/acsaem.8b00884ISI: 000458706500043OAI: oai:DiVA.org:liu-176038DiVA, id: diva2:1559324
Note
Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [200900971]; CNPqConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ); CAPESCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); Grant Aneel/COPEL PD [2866-0470-2017]; CAPES-PDSECoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) [88881.134822/2016-01]
2021-06-022021-06-022021-06-02