ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

State filling effects on photoluminescence and photovoltaic characteristic of aluminium-doped CdTe colloidal quantum dots stabilized in aqueous medium

Vijayaraj Venkatachalam, Sasikala Ganapathy, Ilaiyaraja Perumal, Santhanapanneer Devendrapandi, and Arivarasan Ayyaswamy

Crystal Growth Centre, Anna University, Chennai, India

E-mail: sasikalaganapathycgc@gmail.com

Received: 10 September 2020  Accepted: 26 October 2020

Abstract:

CdTe and aluminium (Al)-doped CdTe (Al:CdTe QDs) colloidal quantum dots (QDs) were synthesized through an aqueous route. CdTe and Al:CdTe QDs colloidal quantum dots of different size were obtained by collecting the samples at different refluxing time. The size of the synthesized QDs collected after 6 h of refluxing time was measured to 3.3 and 4.8 nm for Al:CdTe QDs and CdTe QDs, respectively. The size shrinkages of Al:CdTe QDs were due to chlorine ions from AlCl₃ precursor, which controls the growth kinetics of QDs and stabilizes the QDs in the aqueous phase. The size shrinkages of Al:CdTe QDs result in an increase of bandgap from 2.13 to 2.3 eV and congruently blue-shifted absorbance and emission spectra were discerned. The state filling effect, gradual filling of energy state, observed clearly in photoluminescence spectra of Al:CdTe QDs for samples collected after 30 min of refluxing time. We also fabricated Gratzel-type QDs-sensitized solar cells by loading CdTe and Al:CdTe QDs on mesoporous TiO₂ photoanode. Photovoltaic efficiency is marginally increased (13%) from 0.45 to 0.51% for Al-doped CdTe QDs as compared to CdTe QDs.

Keywords: Cadmium telluride; Quantum dots; State-filling effect; Aliovalent doping; Solar cell

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01406-9

Chemical Papers 75 (5) 1883–1892 (2021)