Vatsasri Raman

Advisor: Dr. Juan-Pablo, Correa-Baena

will defend a Master’s thesis entitled,

DESIGN OF A DIKETOPYRROLOPYROLE-BASED POLYMER FOR EFFICIENT AND STABLE PEROVSKITE PHOTOVOLTAICS

On

Tuesday, April 22nd at 03:00 p.m.
102A Joseph M. Pettit Microelectronics Research

and

Virtually via MS Teams

https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZWVlZWU0NTEtNTAzMi00ZGZmLTliZTYtZDMxMjhiOTBmZmZi%40thread.v2/0?context=%7b%22Tid%22%3a%22482198bb-ae7b-4b25-8b7a-6d7f32faa083%22%2c%22Oid%22%3a%225915c786-3146-4956-bec7-17a8c4d760ce%22%7d

Committee
            Prof. Juan-Pablo Correa-Baena – School of MSE (Advisor)

Prof. Jason D. Azoulay – School of Chemistry and Biochemistry
            Dr. Carlo Perini – School of MSE

Abstract
Perovskite solar cells (PSCs) have emerged as a highly efficient and low-cost photovoltaic technology, achieving power conversion efficiencies (PCEs) over 26%. However, their widespread adoption is limited by poor stability, often worsened by the hygroscopic dopants used in conventional hole transport layers (HTLs) like 2,2′,7,7′-tetrakis (N, N-p-dimethoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD), a small molecule HTL and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] PTAA, a polymer HTL. To overcome this, dopant-free HTLs with high intrinsic mobility and thermal stability are critical. This study investigates a diketopyrrolopyrrole (DKP)-based donor–acceptor conjugated polymer incorporating (E)-2-(2-thiophen-2-yl) vinyl) thiophene (TVT) as a dopant-free HTL. The polymer exhibits a narrow band gap, strong intramolecular charge transfer, and quinoidal character, leading to high planarity and excellent π–π stacking. These features enable a high hole mobility of 1.26 × 10⁻² cm² V⁻¹ s⁻¹ without doping. We evaluate its absorption properties, energy level alignment, film morphology, and photovoltaic performance in perovskite solar cells. The material’s hydrophobic nature and stable charge transport properties offer a promising path toward eliminating dopant-related degradation. Integrating this polymer as a HTL can yield comparable efficiencies to conventional doped layers, while significantly enhancing device stability. This work highlights the potential of narrow band gap donor–acceptor polymers in advancing the next generation of stable, efficient perovskite solar cells.