Hybrid P3HT/CdSe Photovoltaic Cells: Effects of Nanocrystal Size and Device Aging
- PDF / 399,806 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 68 Downloads / 167 Views
1212-S11-07
Hybrid P3HT/CdSe photovoltaic cells: effects of nanocrystal size and device aging Jihua Yang, Renjia Zhou, Aiwei Tang, Jiangeng Xue Department of Material Science and Engineering, University of Florida, Gainesville, FL 32611, USA
ABSTRACT Hybrid solar cells based on conjugated polymers and colloidally synthesized inorganic nanoparticles have been recognized as an alternative to all-organic solar cells due to the intrinsically higher charge transport property in inorganic component. In this work, CdSe nanoparticles with different sizes, served as the electron acceptor, have been used together with poly(3-hexylthiophene) (P3HT) as the active layer for the hybrid solar cells. The power-conversion efficiency (ηp) of these devices strongly depends on the size of the CdSe nanoparticles, increasing from ηp ~0.5% for 4.0 nm size nanoparticles to ηp ~2.4% for 6.8 nm size nanoparticles under AM 1.5 G solar illumination. Furthermore, the devices also exhibit an unusual initial aging period when exposed to the air, which results in a significant enhancement in the short-circuit current, open-circuit voltage and power conversion efficiency. INTRODUCTION Organic solar cells have received considerate attention for their advantages in low-cost, mechanical flexibility, and compatibility with roll-to-roll or printing processing techniques [1-3]. Solution-processable organic solar cells with a donor-acceptor bulk heterojunction structure in the active layer have been recognized as a promising route towards high performance [1, 4]. The bulk heterojunction structure consisting of a bicontinous network of two organic components enables fast separation of electron-hole pair after exciton generation and thus decreases the exciton combination. However, the low carrier mobilities within organic materials severely limit the efficient transport and extraction of charge carriers from the device active layer [5]. Hybrid organic-inorganic solar cells, possessing the processibility of all-organic solar cells, have been considered as an alternative towards high efficiency energy-harvesting devices [6]. Compared to the all-organic counterpart, an inorganic material has been introduced into the hybrid solar cells, which both enables the efficient charge transfer at the organic-inorganic interface as well as promoting the fast carrier transport due to the higher electron mobility [6]. Inorganic nanocrystals, such as CdSe nanoparticles [7], nanorods [6], tetrapods [8], and ZnO nanoparticles [9], have been synthesized and introduced into hybrid solar cells. Although several works have demonstrated efficient solar cells based on inorganic nanocrystals with conjugated polymers such as poly(3-hexylthiophene) (P3HT). These devices have showed relatively low power conversion efficiencies (PCE) (around 2-3%). Devices based on CdSe nanospheres have shown particularly low efficiency less than 1% [6, 7]. The low PCE of these hybrid devices based on CdSe nanospheres was likely due to the inefficient electron transport by multiply hopping steps among
Data Loading...
