TY - JOUR
T1 - Improved hole mobility and suppressed trap density in polymer-polymer dual donor based highly efficient organic solar cells
AU - Bharti, Vishal
AU - Sharma, Abhishek
AU - Gupta, Vinay
AU - Sharma, Gauri D.
AU - Chand, Suresh
N1 - Funding Information:
The authors are grateful to the director, CSIR-National Physical Laboratory, New Delhi, India, for his encouragement. V.B. is grateful to University Grant Commission, Government of India for SRF fellowship. A.S. fellowship is supported by CSIR-TAPSUN (NWP-54) program. All authors are thankful to the CSIR-TAPSUN (NWP-54) program. Author acknowledges the technical support of Sandeep Singh, Ramil Bharadwaj and Neeraj Chaudhary.
Publisher Copyright:
© 2016 AIP Publishing LLC.
PY - 2016/2/15
Y1 - 2016/2/15
N2 - Here we report, the charge transport properties of polymer-polymer dual donor blended film, viz., polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) and poly [N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′benzothiadiazole) (PCDTBT) in the optimized concentration. Trap density and hole mobility in polymer-polymer (PTB7-PCDTBT) dual donor system have been studied by means of current density-voltage (J-V) characteristics at various temperatures, i.e., 280 K-120 K in hole only device configuration, i.e., indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) (PEDOT:PSS)/Polymer film/gold (Au). The J-V curves exhibit the space charge limited conduction behavior. The corresponding hole mobility for PTB7 and PCDTBT are 3.9 × 10-4 cm2 V-1 s-1 and 2.1 × 10-4 cm2 V-1 s-1, respectively, whereas it is 9.1 × 10-4 cm2 V-1 s-1 in the polymer-polymer blend of PTB7:PCDTBT (0.7:0.3). This enhancement in mobility can be attributed to the suppressed trap density in PTB7:PCDTBT (0.7:0.3) of 7.4 × 1016cm-3, as compared to the trap density of 1.1 × 1017cm-3 for PTB7 and 1.6 × 1017cm-3 for PCDTBT. Atomic force microscopy shows an improvement in the morphology of the blend. The J-V characteristic at various light intensities in the bulk heterojunction (BHJ) solar cell reveals that the blending of PCDTBT in PTB7 suppressed the trap-assisted recombination. The corresponding power conversion efficiencies for PTB7:PC71BM, PCDTBT:PC71BM and PTB7:PCDTBT:PC71BM BHJ solar cells are 6.9%, 6.1% and 9.0%, respectively. This work unravels that the enhanced mobility and suppressed trap density play a significant role in the improvement of efficiency in dual donor based organic solar cells.
AB - Here we report, the charge transport properties of polymer-polymer dual donor blended film, viz., polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) and poly [N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′benzothiadiazole) (PCDTBT) in the optimized concentration. Trap density and hole mobility in polymer-polymer (PTB7-PCDTBT) dual donor system have been studied by means of current density-voltage (J-V) characteristics at various temperatures, i.e., 280 K-120 K in hole only device configuration, i.e., indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) (PEDOT:PSS)/Polymer film/gold (Au). The J-V curves exhibit the space charge limited conduction behavior. The corresponding hole mobility for PTB7 and PCDTBT are 3.9 × 10-4 cm2 V-1 s-1 and 2.1 × 10-4 cm2 V-1 s-1, respectively, whereas it is 9.1 × 10-4 cm2 V-1 s-1 in the polymer-polymer blend of PTB7:PCDTBT (0.7:0.3). This enhancement in mobility can be attributed to the suppressed trap density in PTB7:PCDTBT (0.7:0.3) of 7.4 × 1016cm-3, as compared to the trap density of 1.1 × 1017cm-3 for PTB7 and 1.6 × 1017cm-3 for PCDTBT. Atomic force microscopy shows an improvement in the morphology of the blend. The J-V characteristic at various light intensities in the bulk heterojunction (BHJ) solar cell reveals that the blending of PCDTBT in PTB7 suppressed the trap-assisted recombination. The corresponding power conversion efficiencies for PTB7:PC71BM, PCDTBT:PC71BM and PTB7:PCDTBT:PC71BM BHJ solar cells are 6.9%, 6.1% and 9.0%, respectively. This work unravels that the enhanced mobility and suppressed trap density play a significant role in the improvement of efficiency in dual donor based organic solar cells.
UR - http://www.scopus.com/inward/record.url?scp=84960875336&partnerID=8YFLogxK
U2 - 10.1063/1.4942394
DO - 10.1063/1.4942394
M3 - Article
AN - SCOPUS:84960875336
SN - 0003-6951
VL - 108
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 7
M1 - 073505
ER -
