Vacuum-free lamination via controlled polymer adhesion for selective photogeneration and photodetection

Abstract

This study attempts to develop a reproducible thin-film formation technique called vacuum-free (VF) lamination, which transfers thin films using elastomeric polymer-based laminating mediators. Precisely, by controlling the interface characteristics of the mediator based on the work of adhesion, VF lamination is successfully performed for various thicknesses (from 20 to 240 nm) of a conjugated photoactive material composed of poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-bMODIFIER LETTER PRIME]dithiophene))-alt-(5,5-(1MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME-di-2-thienyl-5MODIFIER LETTER PRIME,7MODIFIER LETTER PRIME-bis(2-ethylhexyl)benzo[1MODIFIER LETTER PRIME,2MODIFIER LETTER PRIME-c:4MODIFIER LETTER PRIME,5MODIFIER LETTER PRIME-cMODIFIER LETTER PRIME]dithiophene-4,8-dione)] (a polymer donor) and 2,2MODIFIER LETTER PRIME-((2Z,2MODIFIER LETTER PRIMEZ)-((12,13-bis(2-butyloctyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2MODIFIER LETTER PRIMEMODIFIER LETTER PRIME,3MODIFIER LETTER PRIMEMODIFIER LETTER PRIME:4MODIFIER LETTER PRIME,5MODIFIER LETTER PRIME]thieno[2MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME:4,5]pyrrolo[3,2-g]thieno[2MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (a nonfullerene acceptor). Interestingly, the organic photovoltaic and photodetecting applications, prepared by the VF lamination process, showed superior performance compared to those of devices prepared by conventional spin-coating. This is due to the overturned surface morphology, which led to enhanced charge transport ability and blocking of the externally injected charge. Thus, the reproducible VF lamination process, exploiting an adhesion-based elastomeric polymer mediator, is a promising thin-film formation technique for developing efficient next-generation organic optoelectronic materials consistent with the solution process. Efficient organic electronic devices were fabricated using a vacuum-free (VF) lamination process considering the adhesion between the mediator and poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-bMODIFIER LETTER PRIME]dithiophene))-alt-(5,5-(1MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME-di-2-thienyl-5MODIFIER LETTER PRIME,7MODIFIER LETTER PRIME-bis(2-ethylhexyl)benzo[1MODIFIER LETTER PRIME,2MODIFIER LETTER PRIME-c:4MODIFIER LETTER PRIME,5MODIFIER LETTER PRIME-cMODIFIER LETTER PRIME]dithiophene-4,8-dione)]:2,2MODIFIER LETTER PRIME-((2Z,2MODIFIER LETTER PRIMEZ)-((12,13-bis(2-butyloctyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2MODIFIER LETTER PRIMEMODIFIER LETTER PRIME,3MODIFIER LETTER PRIMEMODIFIER LETTER PRIME:4MODIFIER LETTER PRIME,5MODIFIER LETTER PRIME]thieno[2MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME:4,5]pyrrolo[3,2-g]thieno[2MODIFIER LETTER PRIME,3MODIFIER LETTER PRIME:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile as a photoactive layer. The optimized photovoltaic (PV) and photodetecting (PD) applications based on the VF lamination showed superior PV and PD performances than those of the spin-coated devices owing to not only the improvement of internal charge transport ability and resistances but also the suppressed dark current by a surface-morphology reversal effect. image