title: Multi-source/component spray coating for polymer solar cells.
abstract: A multi-source/component spray coating process to fabricate the photoactive layers in polymer solar cells is demonstrated. Well-defined domains consisting of polymer:fullerene heterojunctions are constructed in ambient conditions using an alternating spray deposition method. This approach preserves the integrity of the layer morphology while forming an interpenetrating donor (D)/acceptor (A) network to facilitate charge transport. The formation of multi-component films without the prerequisite of a common solvent overcomes the limitations in conventional solution processes for polymer solar cells and enables us to process a wide spectrum of materials. Polymer solar cells based on poly(3-hexylthiophene):[6,6]-phenyl C(61) butyric acid methyl ester spray-coated using this alternating deposition method deliver a power conversion efficiency of 2.8%, which is comparable to their blend solution counterparts. More importantly, this approach offers the versatility to independently select the optimal solvents for the donor and acceptor materials that will deliver well-ordered nanodomains. This method also allows the direct stacking of multiple photoactive polymers with controllable absorption in a tandem structure even without an interconnecting junction layer. The introduction of multiple photoactive materials through multisource/component spray coating offers structural flexibility and tenability of the photoresponse for future polymer solar cell applications.
authors.affiliation: Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA.
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Chen
authors.forename: Ziruo
authors.initials: Z
authors.lastname: Hong
authors.forename: Wei Lek
authors.initials: WL
authors.lastname: Kwan
authors.forename: Cheng-Hsueh
authors.initials: CH
authors.lastname: Lu
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Lai
authors.forename: Bao
authors.initials: B
authors.lastname: Lei
authors.forename: Chuan-Pu
authors.initials: CP
authors.lastname: Liu
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang