Further optimization of the cell is possible for achieving higher efficiencies. Acknowledgements The authors would like to thank University of Malaya for the IPPP grant no. PV094-2012A. H.K. Jun thanks University of Malaya for the Fellowship AZD2014 Scheme Scholarship. References 1. Jun HK, Careem MA, Arof AK: Quantum dot-sensitized solar cells–perspective

and recent developments: a review of Cd chalcogenide quantum dots as sensitizers. Renew Sust Energ Rev 2013, 22:148–167.CrossRef 2. Kamat PV: Quantum dot solar cells: the next big thing in photovoltaics. J Phys Chem Lett 2013, 4:908–918.CrossRef 3. Kamat PV: Quantum dot solar cells: semiconductor nanocrystals as light harvesters. J Phys Chem C 2008, 112:18737–18753.CrossRef 4. Ruhle S,

Shalom M, Zaban A: Quantum-dot-sensitized Y-27632 supplier solar cells. Chem PhysChem 2010, 11:2290–2304.CrossRef 5. Yu W, Qu LH, Guo WZ, Peng XG: Experimental determination of the extinction coefficient of CdTe, CdSe and CdS nanocrystals. Chem Mater 2003, 15:2854–2860.CrossRef 6. Tibtumtae A, Wu K-L, Tung H-Y, Lee M-W, Wang GJ: Ag 2 S quantum dot-sensitized solar cells. Electrochem Commun 2010, 12:1158–1160.CrossRef 7. Vogel R, Pohl K, Weller H: Sensitization of highly porous, polycrystalline TiO 2 electrodes by quantum sized CdS. Chem Phys Lett 1990, 174:241–246.CrossRef 8. Robel I, Subramanian V, Kuno M, Kamat PV: Quantum dot solar cells: harvesting light energy with CdSe nanocrystals molecularly linked to mesoscopic TiO 2 films. J Am Chem Soc 2006, 128:2385–2393.CrossRef 9. Plass R, Pelet S, Krueger J, Gratzel M, Bach U: Quantum dot sensitization of organic–inorganic hybrid solar cells. J Phys Chem

B 2002, 106:7578–7580.CrossRef 10. Chang J-Y, Su L-F, Li C-H, Chang C-C, Lin J-M: Efficient “green” quantum dot-sensitized solar cells based on Cu 2 S-CuInS 2 -ZnSe architecture. Chem Commun 2012, 48:4848–4850.CrossRef 11. Kim H-S, Lee J-W, Yantara N, Boix PP, Kulkarni SA, Mhaisalkar S, Gratzel BCKDHA M, Park N-G: High efficiency solid-state sensitized solar cell-based on submicrometer rutile TiO 2 nanorod and CH 3 NH 3 PbI 3 perovskite sensitizer. Nano Lett 2013, 13:2412–2417.CrossRef 12. Gratzel M: Conversion of sunlight to electric power by nanocrystalline dye-sensitized solar cells. J Photochem Photobiol A Chem 2004, 164:3–14.CrossRef 13. Mora-Sero I, Bisquert J: Breakthroughs in the development of semiconductor-sensitized solar cells. J Phys Chem Lett 2010, 1:3046–3052.CrossRef 14. Kiyogana T, Akita T, Tada H: Au nanoparticle electrocatalysis in photoelectrochemical solar cell using CdS quantum dot-sensitized TiO 2 photoelectrodes. Chem Commun 2009, 15:2011–2013. 15. Shen Q, Yamada A, Tamura S, Toyoda T: CdSe quantum dot-sensitized solar cell employing TiO 2 nanotube working-electrode and Cu 2 S counter-electrode. Appl Phys Lett 2010, 97:123107.CrossRef 16.