| Full text | |
| Author(s): Show less - |
Tazawa, Yujiro
[1]
;
Habisreutinger, Severin N.
[2, 3]
;
Zhang, Nanlin
[1]
;
Gregory, Daniel A. F.
[1]
;
Nagamine, Gabriel
[4]
;
Kesava, Sameer V.
[2]
;
Mazzotta, Giulio
[2]
;
Assender, Hazel E.
[1]
;
Riede, Moritz
[2]
;
Padilha, Lazaro A.
[4]
;
Nicholas, Robin J.
[2]
;
Watt, Andrew A. R.
[1]
Total Authors: 12
|
| Affiliation: | [1] Univ Oxford, Dept Mat, 16 Parks Rd, Oxford OX1 3PH - England
[2] Univ Oxford, Clarendon Lab, Dept Phys, Parks Rd, Oxford OX1 3PU - England
[3] Natl Renewable Energy Lab, Chem & Nanosci Ctr, 15013 Denver West Pkwy, Golden, CO 80401 - USA
[4] Univ Estadual Campinas, Inst Fis Gleb Wataghin, Rua Sergio Buarque de Holanda 777, BR-13083859 Campinas, SP - Brazil
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | ACS PHOTONICS; v. 5, n. 12, p. 4854-4863, DEC 2018. |
| Web of Science Citations: | 1 |
| Abstract | |
Colloidal quantum dot (CQD)-based photo-voltaics are an emerging low-cost solar cell technology with power conversion efficiencies exceeding 10%, i.e., high enough to be interesting for commercialization. Well-controlled and understood charge carrier transport through the device stack is required to make the next step in efficiency improvements. In this paper, polymer-wrapped single-walled carbon nanotube (SWNT) films embedded in an insulating poly(methyl methacrylate) (PMMA) matrix and capped by a thermally evaporated Au electrode are investigated as a composite hole transport layer and optical spacer. Employing transient absorption spectroscopy we show that the SWNTs enhance the charge transfer rate from CQD to CQD, ZnO, or SWNT. In order to pinpoint the underlying mechanism for the improvement, we investigate the energetics of the junction by measuring the relative alignment of the band edges, using Kelvin probe and cyclic voltammetry. Measuring the external quantum efficiency and absorption we find that the improvement is not mainly from electronic improvements but from enhanced absorption of the CQD absorber. We demonstrate experimentally and theoretically, by employing a transfer-matrix model, that the transparent PMMA matrix acts as an optical spacer, which leads to an enhanced absorption in the absorber layer. With these electronic and optical enhancements, the efficiency of the PbS CQD solar cells improved from 4.0% to 6.0%. (AU) | |
| FAPESP's process: | 13/16911-2 - Advanced spectroscopy of novel nanomaterials |
| Grantee: | Lázaro Aurélio Padilha Junior |
| Support Opportunities: | Research Grants - Young Investigators Grants |