Direct assembly of thioacid capped quantum dots in solid-state hybrid photovoltaics, effect of QDs size and thermal annealing
Por:
Triana, Manuel A., Jaramillo-Quintero, Oscar A., Camargo, Ruben J., Rincon, Marina E.
Publicada:
1 ene 2017
Resumen:
Deposition of colloidal quantum dot thin films to fabricate hybrid solar
cells is strongly dependent on the nature of the quantum dot (QD)
surface ligand. In order to reduce the fabrication cost and eliminate
additional steps as the ligand-exchange, water soluble quantum dots
(WSQDs) can be directly assembled in solid-state hybrid photovoltaics.
In this paper we present the synthesis and characterization of solution
processed quantum dot solar cells (QDSCs) with mercaptosuccinic acid
(MSA) capped CdSe QDs as the active layer, rutile TiO2 nanorods (NRs) as
the electron transport material (ETM) and Spiro-OMeTAD as the hole
transport material (HTM). Narrow size distribution and surface
coordination of the WSQDs were critical on the performance of the
devices, with 3.5 nm CdSe QDs yielding the best power conversion
efficiency (PCE). Annealing of the CdSe QD layer at 190 degrees C and
room temperature infiltration of SpiroOMeTAD into the active layer,
simultaneously increased V-oc, J(sc), and PCE. Proper annealing
increases the QD size and removes linked water and excess ligands,
contributing to QD packing and better electron-transport through the
active layer. The improvement of Voc observed after further HTM
infiltration, can be ascribed to the surface passivation of in-gap trap
states and weak p-doping of QDs induced by 4-tert-butylpyridine, as
evidenced by Kelvin probe measurements.
Filiaciones:
Triana, Manuel A.:
Univ Valle, Escuela Ingn Quim, Ciudad Univ Melendez,AA 25360, Cali, Colombia
Jaramillo-Quintero, Oscar A.:
Univ Nacl Autonoma Mexico, Inst Energias Renovables, Privada Xochicalco S-N, Temixco 62580, Mor, Mexico
Camargo, Ruben J.:
Univ Valle, Escuela Ingn Quim, Ciudad Univ Melendez,AA 25360, Cali, Colombia
Rincon, Marina E.:
Univ Nacl Autonoma Mexico, Inst Energias Renovables, Privada Xochicalco S-N, Temixco 62580, Mor, Mexico
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