New Physics: Sae Mulli, Vol. 65, No. 7, July 2015, pp. 709 714 DOI: 10.3938/NPSM.65.709 Efficiency Enhancement in Polymer Solar Cell Using Solution-processed Vanadium Oxide Hole Transport Layer Insoo Shin Hoyeon Choi Sung Heum Park Department of Physics, Pukyong National University, Busan 608-737, Korea (Received 10 May 2015 : revised 18 June 2015 : accepted 21 June 2015) Polymer solar cells are considered as promising candidates for the next generation energy source due to their advantage including low cost and large-area fabrication and mechanical flexibility. We reported the efficiency enhancement in a polymer solar cell with a solution-processed vanadium oxide hole transport layer. When we inserted a solution-based vanadium sub-oxide layer in between the polymer blending layer and the indium tin oxide anode, the polymer solar cells exhibit an enhanced efficiency compared with that without the vanadium sub-oxide layer. Moreover, the efficiency of polymer solar cells are 27% higher than that of the polymer solar cells with a conventional PEDOT:PSS layer which is widely used as hole transport layer. PACS numbers: 42.70.Jk, 71.20.Rv, 71.20.Tx, 73.50.Pz, 73.61.Ph Keywords: Organic solar cell, Bulk Heterojunction, Vanadium Oxide, Buffer layer, 608-737 (2015 5 10, 2015 6 18, 2015 6 21 ). (VO X). VOx כ,,., PEDOT:PSS 27%. PACS numbers: 42.70.Jk, 71.20.Rv, 71.20.Tx, 73.50.Pz, 73.61.Ph Keywords:,,, E-mail: spark@pknu.ac.kr This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
710 New Physics: Sae Mulli, Vol. 65, No. 7, July 2015 I., [1 3].,,. (Indium Tin Oxide, ITO)., ITO ITO (Power Conversion Efficiency, PCE)., ITO ITO [4 7]. Poly(3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT:PSS),, [8]., PEDOT:PSS (sulfonic acid) ITO. [9 11],, PEDOT:PSS [12]., (VOx), (WOx), (MoOx). VOx,, PEDOT:PSS., VOx, כ VOx כ [13 15]., PEDOT:PSS כ VOx,. VOx PEDOT:PSS, 27%. II.. ITO,,,, 24. UV-Ozone Cleaner 20, PEDOT:PSS VO X, VO X Vanadium oxytriisopropoxide (VOTP) IPA 1:150. PEDOT:PSS 140 C 10, VO X 80 C 10 UV-Ozone Cleaner. Poly[4,8-bis(2-ethylhexyloxy)benzo[1,2- b:4,5-b ]dithiophene-alt22,5-dioctyl-4,6-di(thiophen-2- yl)pyrrolo[3,4-c]pyrrole-1,3(2h,5h)-dione)] (P(BDT- TDPPDT)) Poly[[5-(2-ethylhexyl)-5,6-dihydro- 4,6-dioxo-4H-thieno[3,4-c]pyrrole-1,3-diyl][4,8-bis[(2- ethylhexyl)oxy]benzo[1,2-b:4,5-b ]dithiophene-2,6-diyl]] (PBDTTPD) P(BDT-TDPPDT- TPD) PC 70 BM 1:2.25, 2 wt%,. 100 nm. -, AM1.5G (100 mw/cm 2 )., UV-Ozone VO X Ultraviolet Photoelectron Spectroscopy (UPS). III.,,
Efficiency Enhancement in Polymer Solar Cell Using Solution-processed Insoo Shin et al. 711 Fig. 1. (Color online) (a) Molecular structure of vanadium oxytriisopropoxide (VOTP), (b) transmittance spectrum of vanadium oxide film and picture of VOTP/IPA solution (Inset). Fig. 2. (Color online) (a) Device structure and (b) energy level diagram.,.,, VOx,. Fig. 1(a) VOx VOTP. VOTP, VOx IPA 1:150, 80 C 10. VOTP IPA, Fig. 1(b). Fig. 1(b) VOTP / IPA, VOx. 450 nm 530 nm 530 nm,.,., 90%,, 370 nm 95%, כ., VOTP / IPA VOx. VOx,. Fig. 2(a). ITO, P(BDT-TDPPDT- TPD):PC 70 BM ITO,
712 New Physics: Sae Mulli, Vol. 65, No. 7, July 2015 Fig. 3. (Color online) (a) Energy level variation of VO X film by UV-Ozone treatment, (b) current and voltage characteristics of device with and without UV-Ozone treatment. PEDOT:PSS VO X, ITO (4.8 ev) (4.3 ev). Fig. 2(b) כ. (exciton) (P(BDT-TDPPDT-TPD)) (PC 70 BM),, ITO. ITO, ITO,, כ. כ [16,17]., כ. VO X, PEDOT:PSS (Highest occupied molecular orbital, HOMO) (Lowest unoccupied molecular orbital, LUMO). PEDOT:PSS, VO X, כ, כ [14, 18]., VO X,.,. UV-Ozone. UV- Ozone Cleaner,,, (oxygen vacancy), כ [15, 19]., VO X UV-Ozone Cleaner,, כ. Fig. 3(a) UPS UV-Ozone VO X כ. UV-Ozone, VO X כ. VOx -8.28 ev UV-Ozone 5-7.51 ev, 10-7.52 ev, 15-7.26 ev, VOx, -5.8 ev 5-5.05 ev, 10-5.23 ev, 15-4.84 ev. UV-Ozone כ, 5., VO X, VO X כ כ, 10 UV-Ozone. UV-Ozone VO X
Efficiency Enhancement in Polymer Solar Cell Using Solution-processed Insoo Shin et al. 713 Table 1. Data of Jsc, Voc, FF and Efficiency for device with VO X HTL with and without UV-Ozone treatment. HTL Jsc (ma/cm 2 ) Voc (V) FF Efficiency (%) VO X w/o UV 8.77 0.76 0.65 4.29 VO X with UV 8.84 0.85 0.68 5.15 Table 2. Data of Jsc, Voc, FF and Efficiency for device with VO X and PEDOT:PSS HTL. HTL Jsc (ma/cm 2 ) Voc (V) FF Efficiency (%) PEDOT:PSS 8.44 0.76 0.68 4.33 VO X with UV 8.84 0.87 0.71 5.5, UV-Ozone VO X J-V, UV-Ozone. Fig. 3(b) UV VO X 10 UV VO X J-V כ,,,, Table 1. UV-Ozone 8.77 ma/cm 2 8.84 ma/cm 2, 0.65 0.68, 0.76 V 0.85 V 12%, 4.29% 5.15% 20%. UV-Ozone,. Fig. 3(a), UV-Ozone VOx ITO.,, כ., VOx UV-Ozone כ,, כ. Fig. 3(a), (b), VOTP / IPA VOx UV-Ozone, VOx. VOx Fig. 4. (Color online) Current and voltage characteristics of device with VOx and PEDOT:PSS layer as a hole transport layer., PEDOT:PSS, VOx. Fig. 4 PEDOT:PSS, - כ. Table 2, PEDOT:PSS UV-Ozone VO X, 8.44 ma/cm 2 8.84 ma/cm 2, 0.68 0.71, 0.76 V 0.87 V 14%, UV-Ozone VO X כ., 4.33% 5.5% 27%., VOx, PEDOT:PSS. IV., PEDOT:PSS. VOTP IPA,
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