Highly efficient polymer solar cells based on a universal cathode interlayer composed of metallophthalocyanine derivative with good film-forming propertyElectronic supplementary information (ESI) available: Details of UV/vis absorption spectrum and electrochemical properties of ZnPc(OC8H17OPyCH3I)8, J-V characteristics of electron-only and hole-only devices and curves of the PSCs based on P3HT:PC61BM, PCDTBT:PC71BM with the various cathodes. See DOI: 10.1039/c4ta06601d

• Main Authors: Jia, Tao, Zhou, Weilong, Chen, Youchun, Han, Jianxiong, Wang, Lu, Li, Fenghong, Wang, Yue
• Format: Journal Article
• Language: English
• Published: 10.02.2015
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c4ta06601d

A new cathode interlayer (CIL) material metallophthalocyanine (MPc) derivative 1,4,8,11,15,18,22,25-octaoctyloxy-2,3,9,10,16,17,23,24-octa-[ N -methyl-(3-pyridyloxy)] zinc-ylphthalocyanine iodide (1 : 8) (ZnPc(OC 8 H 17 OPyCH 3 I) 8 ) was synthesized and applied in polymer solar cells (PSCs) based on PTB7:PC 71 BM (PTB7 = thieno[3,4- b ]thiophene/benzodithiophene, PC 71 BM = [6,6]-phenyl C71-butyric acidmethyl ester), P3HT:PC 61 BM (P3HT = poly(3-hexylthiophene), PC 61 BM = [6,6]-phenyl C61-butyric acidmethyl ester) or PCDTBT:PC 71 BM (PCDTBT = poly[ N -9′′-heptadecanyl-2,7-carbazole- alt -5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]) as an active layer. As a result, power conversion efficiency (PCE) values of the PSCs were 8.52%, 4.02% and 6.88%, respectively, which are much higher than those of corresponding PSCs with the Al-only cathode. It indicates that ZnPc(OC 8 H 17 OPyCH 3 I) 8 is a new promising candidate as a universal CIL for highly efficient PSCs. Compared to VOPc(OPyCH 3 I) 8 (2,3,9,10,16,17,23,24-octakis-[ N -methyl-(3-pyridyloxy)] vanadylphthalocyanine iodide (1 : 8)), the PSC with ZnPc(OC 8 H 17 OPyCH 3 I) 8 as a CIL has higher short-circuit current and fill factor because ZnPc(OC 8 H 17 OPyCH 3 I) 8 can form a better, denser, and more uniform film on the active layer than VOPc(OPyCH 3 I) 8 as demonstrated by atomic force microscopy (AFM), energy-dispersive spectrum mapping on scan electron microscopy (SEM-EDS mapping) and contact angle measurements. ZnPc(OC 8 H 17 OPyCH 3 I) 8 with good adhesion to active layer has been utilized as a cathode interlayer for highly efficient polymer solar cells.