Charge Accumulation, Recombination, and Their Associated Time Scale in Efficient (GUA) x (MA)1- x PbI3-Based Perovskite Solar Cells

Daniel Prochowicz; Mohammad Mahdi Tavakoli; Anwar Q Alanazi; Suverna Trivedi; Hadi Tavakoli Dastjerdi; Shaik M Zakeeruddin; Michael Grätzel; Pankaj Yadav

doi:10.1021/acsomega.9b01701

Charge Accumulation, Recombination, and Their Associated Time Scale in Efficient (GUA) _x (MA)_{1- x} PbI₃-Based Perovskite Solar Cells

ACS Omega. 2019 Oct 3;4(16):16840-16846. doi: 10.1021/acsomega.9b01701. eCollection 2019 Oct 15.

Authors

Daniel Prochowicz^{1

2}, Mohammad Mahdi Tavakoli^{3

4}, Anwar Q Alanazi², Suverna Trivedi⁵, Hadi Tavakoli Dastjerdi³, Shaik M Zakeeruddin², Michael Grätzel², Pankaj Yadav⁵

Affiliations

¹ Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
² Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
³ Department of Electrical Engineering and Computer Science and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
⁴ Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran, Iran.
⁵ Department of Chemical Engineering, School of Technology and Department of Solar Energy, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, Gujarat, India.

Abstract

Here, we study the influence of guanidinium (GUA) ions on the open-circuit voltage (V _oc) in the (GUA) _x (MA)_1-x PbI₃ based perovskite solar cells. We demonstrate that incorporation of GUA forms electronic and ionic accumulation regions at the interface of the electron transporting layer and perovskite absorber layer. Our electrochemical impedance spectroscopy results prove that the formed accumulation region is associated with the enhanced surface charge capacitance and photovoltage. Furthermore, we also demonstrate the influence of the GUA ions on the enhanced interfacial and bulk electronic properties due to more efficient charge transfer between the bulk and interfaces and the reduced electronic defect energy levels.