Ultra-thick semi-crystalline photoactive donor polymer for efficient indoor organic photovoltaics

Sang Chul Shin, Chang Woo Koh, Premkumar Vincent, Ji Soo Goo, Jin Hyuk Bae, Jae Joon Lee, Changhwan Shin, Hyeok Kim, Han Young Woo, Jae Won Shim

Research output: Contribution to journalArticlepeer-review

67 Citations (Scopus)


An in-depth study on the photovoltaic characteristics under indoor lights, i.e., light-emitting diode (LED), fluorescent lamps, and halogen lamps, was performed with varying the photoactive layer thickness (120–870 nm), by comparing those under 1-sun condition. The semi-crystalline mid-gap photoactive polymer, poly[(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole)] (PPDT2FBT) and a fullerene derivative, [6,6]-phenyl C 71 butyric acid methyl ester (PC 70 BM) were used as a photoactive layer. In the contrary to the measurements under 1-sun condition, the indoor devices show a clearly different behavior, showing the thickness tolerant short-circuit current density (J SC ) and fill factor (FF) values with 280–870 nm thick photoactive layers. The retained J SC and FF values of thick indoor devices were discussed in terms of the parasitic resistance effects based on the single-diode equivalent circuit model. The much lower series/shunt resistance (Rs/R P ) ratio was measured with thick photoactive layer (≥280 nm), resulting in negligible decreases in the J SC and FF values even with a 870-nm-thick active layer under the LED condition. Under 1000 lx LED light, the PPDT2FBT:PC 70 BM device showed an optimum power conversion efficiency (PCE) of 16% (max power density, 44.8 μW/cm 2 ) with an open-circuit voltage of 587 mV, a J SC of 117 μA/cm 2 , and a FF of 65.2. The device with a 870-nm-thick active layer still exhibited an excellent performance with a PCE of 12.5%. These results clearly suggest that the critical parasitic resistance effects on the performance vary depending on the light illumination condition, and the large R P associated with the viable thick photoactive layer and the well-matched absorption (of photoactive layer) with the irradiance spectrum (of indoor light) are essential to realize efficient indoor photovoltaic cells with high J SC and FF.

Original languageEnglish
Pages (from-to)466-475
Number of pages10
JournalNano Energy
Publication statusPublished - 2019 Apr


  • Indoor light conditions
  • Organic photovoltaics
  • Poly[(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c][1,2, 5]thiadiazole)]
  • Semi-crystalline polymer
  • Single-diode equivalent circuit model
  • Ultra-thick photoactive layer

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering


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