Grating Formation by Periodic Photopolymerization in Organic Photovoltaic Devices

Electron Donor and Acceptor Spatial Distribution in Structured Bulk Heterojunction Photovoltaic Devices Induced by Periodic Photopolymerization

“…23−25 However, we previously reported the formation of photorefractive grating in films made of electron donor (3-formyl-9vinylcarbazole, VCz(CHO)) and an electron acceptor (2,4,7trinitro-9-fluorenone, TNF). 26 Periodic photopolymerization induced a gradient of carbazole density distribution in the films, resulting in the controlled formation of a periodic refractive index pattern. 27 In addition, VCz(CHO) films are very soft at room temperature, and such liquid carbazoles were recently used as a hole transport material, 28 as well as organic light emitting diodes 29 and hybrid organic−inorganic bistable memory devices.…”

“…All optical methods to fabricate optoelectronic structured thin films are largely dominated by azobenzene derivative. − However, we previously reported the formation of photorefractive grating in films made of electron donor (3-formyl-9-vinylcarbazole, VCz(CHO)) and an electron acceptor (2,4,7-trinitro-9-fluorenone, TNF) . Periodic photopolymerization induced a gradient of carbazole density distribution in the films, resulting in the controlled formation of a periodic refractive index pattern .…”

“…Therefore, we have started to investigate structured BHJ photovoltaic devices fabricated with VCz(CHO) and C 61 -butyric acid methyl ester (PCBM) to take further advantage of softness and photopolymerization properties of the liquid carbazole. We already demonstrated that surface relief gratings (SRGs) were formed in the structured BHJ devices, , uniquely forming SRGs in films without azobenzene compounds. − …”

In Situ KPFM Imaging of Local Photovoltaic Characteristics of Structured Organic Photovoltaic Devices

“…36−38 We previously reported the formation of photorefractive gratings in films made of the electron donor 3-formyl-9vinylcarbazole (VCz(CHO)) and the electron acceptor 2,4,7trinitro-9-fluorenone (TNF). 39 Periodic photopolymerization induced a gradient of carbazole density along the films, which resulted in the controlled formation of a periodic refractiveindex pattern. 40 Additionally, VCz(CHO) films are very soft at room temperature, and these liquid carbazoles have recently been used as hole-transport materials, 41 organic light-emitting diodes, 42 and hybrid organic−inorganic bistable memory devices.…”

“…We have demonstrated the formation of SRGs and D/A spatial distribution in the structured devices, which resulted in observably enhanced photocurrents. 39,44 D/A spatial distribution was formed in the structured photovoltaic devices, and PCBM molecules were highly distributed in the upper regions of the grating. 44−47 Herein, we report on our investigation of the macroscopic and local photovoltaic properties in the structured photovoltaic devices.…”