Quantum Confined TiO2 induced Co-Sensitization for Superior Performance of QDDSSC

Varsha Khare^a, Sanjiv Sonkaria^a, Sung-Hoon Ahn^a, Caroline Sunyong Lee^b, Dahyun Choi^b, Suhee Kang^b, ShivRaj Poudel^c

^aInstitute of Advanced Machinery and Design,, Innovative Design and Integrated Manufacturing Lab,Seoul National University, 1 Gwanak-ro, Gwanak-gu , Seoul, 151, Korea, Republic of

^bDepartmeneringt of Materials Engineering, Multi-Functional Materials & Devices Lab. 5th Engineering Building, Rm. #318 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, Gyeonggi-do, Korea, Republic of

^cSchool of Mechanical and Aerospace Engine, Innovative Design and Integrated Manufacturing Lab,Seoul National University, 1 Gwanak-ro, Gwanak-gu , Seoul, 151, Korea, Republic of

International Conference on Hybrid and Organic Photovoltaics
Proceedings of International Conference on Hybrid and Organic Photovoltaics 2015 (HOPV15)

Roma, Italy, 2015 May 11th - 13th

Organizer: Filippo De Angelis

Poster, Suhee Kang, 236
Publication date: 5th February 2015

The demand for renewable energy on the scale of 612 quadrillion Btu (33GW/Yr.) by 2020 has led to accelerated research with increasing emphasis on harnessing energy from non-conventional and ‘greener’ sources. Solar energy is recognized as the most abundant and sustainable form of energy and efforts are directed at implementing technologies to increase the efficiency of solar conversion to electricity as effectively as possible. In this context, the design characteristics of dye sensitized solar cells (DSSCs)¹ are of growing interest because of the potential to address the cost effectiveness and the cell performance from the practicality of incorporating functional novel or hybrid materials at low-cost with the advantage of tuning their associated properties to maximize efficiencies. However, despite the tremendous progress in recent years, the desire to achieve sustainable levels of power conversion predominantly relates to enhancing the light harvesting properties of core materials². The suggestion that the addition of quantum confined foreign species can deliver favorable functionalities to improve the working characteristics of DSSCs by preventing exciton recombination has been proven to be a favorable hypothesis so far. Despite the promising alternative, usage of currently available quantum dot materials for TiO₂ sensitization is limited by expense and toxicity. The work undertaken here aims to significantly advance the applicability of this strategy of co-sensitization by implementing a cost-effective and non-hazardous eco-friendly approach. This has been achieved by the successful fabrication of TiO₂ quantum dot materials (particle size within 2nm range) with tunable band gap via surface functionalization. The band gap characteristics are compatible with a broader absorption capacity of lower energy photons spanning the ultraviolet to near infra-red solar spectrum. This also increases their potential to implement their role as accepter and mediator carriers to amplify charge transfer kinetics. Preliminary investigations using TiO₂ QDDSSC signify efficiencies of 7.5% which represents an increase of 0.5% above the reference DSSC. Further, the introduction of graphene as an electron transport channel increases the efficiency of the QDDSSC. A potential mechanistic route based upon charge transfer kinetics is presented which might help demonstrate the existence of an underlying Forster resonance energy transfer process supporting the performance enhancement of TiO2 QDDSSC.

1. O'Regan, B.; Grätzel,M., A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films, Nature 1991, 353 (6346): 737–740. 2. Mathew, S.; Yella, A.; Peng Gao;Humphry-Baker, R.;, F. E. Curchod, B.; Ashari-Astani, N.; Tavernelli, I.; Rothlisberger, U.; Nazeeruddin, M.K. and Gra¨tzel,M., Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers, Nature Chemistry 2014, 6, 242-247.

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International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

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