Organinc Solar Cells

1. Functionalized Carbon Nanotubes as Charge Carrier in Organic Solar Cells Xinbo Cui, Somenath Mitra* Department of Chemistry and Environmental Science, Newark, NJ07102,USA *Email:somenath.mitra@njit.edu C70-CNT Composite Original C70 c-MWNTs-C70 composite UV-Visible absorption spectra of P3HT:c-MWNTS-C70composite gives the strongest light absorption. PL from P3HT was almost completely quenched when the polymer was blended with fullerene at 1:1 weight ratio, as well as P3HT-C70-c-MWNTs composite. Original C70 c-MWNTs-C70 composite Device characterization J-V characteristics under simulated solar irradiation at 95 mW cm-2 J-V characteristics under AM1.5G solar illumination (95 mW/cm2) of annealed PV cells using P3HT:C70 (1:1 wt, dark purple), P3HT:c-MWNTs-C70 (light green), as the active layer. Conclusion Organic solar cells are fabricated by using CNT-C70 complex and a conjugated polymer P3HT. Introduction of CNTs into the composite enhanced Jsc because of faster electron transport via CNT network, leading to improved power conversation efficiency as compared to cells without CNTs. • Organinc Solar Cells • Organic solar cells are a promising low-cost alternative to silicon PV (photovoltaic) solar cells . By using roll-to- roll techniques, it could achieve the speed of 10000m2h-1, which is orders of magnitude faster, comparing to the processing of crystalline silicon. Spin coating is the most commonly used deposition technique in the research laboratories for OPVs, which is easier, cheaper, and is well controllable to obtain high film uniformity as well. • The important processes in an polymer solar cells are • photon absorption, • exciton generation and charge separation, • charge transport. • Why Carbon Nanotubes • While C70is an good electron acceptor, it has poor charge transport capabilities Electron mobility of CNTs is 108×109 cm2/Vs, and hole mobility of CNTs is 103×103 cm2/Vs. As compared to C70, which is 2x10-3 cm2/Vs. The Caron nanotubes function as charge transported. • Why C70 Fullerenes: • C70 fullerenes are electron acceptors that separate an electron and a hole. At the same they show higher photon absorption. • Solution: • To combine effect of charge separation and fast electron transport, we have developed C70-CNT composite. • C70-CNT Solar Cells • A novel immobilized fullerene–carboxylated MWNTs(C70–c-MWNTs) complex was synthesized via a microwave induced functionalization approach. It has been used as a component of the photoactive layer in a bulk heterojunction photovoltaic cell. • The C70–c-MWNTs complex and its role in an OPV is illustrated as shown below. • It was studied by using SEM and UV spectroscopy, and Raman spectroscopy.