Publications de Kasparas Rakstys

Foldable Hole-Transporting Materials for Merging Electronic States between Defective and Perfect Perovskite Sites

Keith Gregory Brooks, Mohammad Khaja Nazeeruddin, Paul Joseph Dyson, Kasparas Rakstys, Yi Zhang, Hiroyuki Kanda, Ruiyuan Hu, Jianxing Xia, Qurat Ul Ain

Defective and perfect sites naturally exist within electronic semiconductors, and considerable efforts to reduce defects to improve the performance of electronic devices, especially in hybrid organic-inorganic perovskites (ABX(3)), are undertaken. Herein, ...

Wiley-V C H Verlag Gmbh2023

Passivating Defects of Perovskite Solar Cells with Functional Donor-Acceptor-Donor Type Hole Transporting Materials

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Yi Zhang, Jianxing Xia

In this study, a series of donor-acceptor-donor (D-A-D) type small molecules based on the fluorene and diphenylethenyl enamine units, which are distinguished by different acceptors, as holetransporting materials (HTMs) for perovskite solar cells is present ...

WILEY-V C H VERLAG GMBH2023

Transparent Liquid Crystal Hole-Transporting Material for Stable Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Hiroyuki Kanda, Jianxing Xia

Hexakis(hexyloxy)triphenylene (HAT6) discotic liquid crystal is employed as a transparent hole-transporting material (HTM) for perovskite solar cells (PSCs) and a power conversion efficiency (PCE) of 15.7% is obtained, which is the highest using HAT6 type ...

WILEY-V C H VERLAG GMBH2023

Branched Fluorenylidene Derivatives with Low Ionization Potentials as Hole-Transporting Materials for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Jianxing Xia

A group of small-molecule hole-transporting materials(HTMs) thatare based on fluorenylidene fragments were synthesized and testedin perovskite solar cells (PSCs). The investigated compounds weresynthesized by a facile two-step synthesis, and their properti ...

AMER CHEMICAL SOC2023

Zn(II) and Cu(II) tetrakis(diarylamine)phthalocyanines as hole-transporting materials for perovskite solar cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Hiroyuki Kanda, Cansu Igci, Nadja Isabelle Desiree Klipfel, Maria Cristina Momblona Rincón, Jianxing Xia, Pavel Culik, Wei Li

Finding new hole-transporting materials (HTMs) suitable for replacing the state-of-the-art spiro-OMe-TAD is still challenging. In this work, newly synthesized diarylamine-substituted metal phthalocyanines (MPcs, M 1/4 Zn(II) or Cu(II)) functionalized with ...

ELSEVIER SCI LTD2022

Green-Chemistry-Inspired Synthesis of Cyclobutane-Based Hole-Selective Materials for Highly Efficient Perovskite Solar Cells and Modules

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Sanghyun Paek, Yi Zhang, Hiroyuki Kanda

Hybrid lead halide perovskite solar cells (PSCs) have emerged as potential competitors to silicon-based solar cells with an unprecedented increase in power conversion efficiency (PCE), nearing the breakthrough point toward commercialization. However, for h ...

Wiley-VCH Verlag GmbH2022

Cut from the Same Cloth: Enamine-Derived Spirobifluorenes as Hole Transporters for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Paul Joseph Dyson, Kasparas Rakstys, Cansu Igci, Albertus Adrian Sutanto, Maria Cristina Momblona Rincón, Bin Ding

To attain commercial viability, perovskite solar cells (PSCs) have to be reasonably priced, highly efficient, and stable for a long period of time. Although a new record of a certified power conversion efficiency (PCE) value over 25% was achieved, PSC perf ...

AMER CHEMICAL SOC2021

Dopant‐Free Hole Transport Materials Afford Efficient and Stable Inorganic Perovskite Solar Cells and Modules

Mohammad Khaja Nazeeruddin, Paul Joseph Dyson, Kasparas Rakstys, Olga Syzgantseva, Hiroyuki Kanda, Cansu Igci, Bin Ding, Yong Ding, Cheng Liu, Xianfu Zhang

The emerging CsPbI3 perovskites are highly efficient and thermally stable materials for wide-band gap perovskite solar cells (PSCs), but the doped hole transport materials (HTMs) accelerate the undesirable phase transition of CsPbI3 in ambient. Herein, a d ...

Wiley-VCH Verlag GmbH2021

Fluorene-based enamines as low-cost and dopant-free hole transporting materials for high performance and stable perovskite solar cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Albertus Adrian Sutanto, Maria Cristina Momblona Rincón

The power conversion efficiency of perovskite solar cells is approaching the Shockley-Queisser limit, and therefore this technology is next to the commercialization stage. Inexpensive and stable hole transporting materials are highly desirable for the succ ...

Royal Society of Chemistry2021

Branched Methoxydiphenylamine-Substituted Carbazole Derivatives for Efficient Perovskite Solar Cells: Bigger Is Not Always Better

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Yi Zhang, Hiroyuki Kanda, Jianxing Xia

A set of novel branched molecules bearing a different number of 3,6-bis(4,4'-dimethoxydiphenylamino)carbazole-based (CzOMeDPA) periphery arms linked together by aliphatic chains have been developed, and their performance has been tested in perovskite solar ...

AMER CHEMICAL SOC2021

Carbazole-Terminated Isomeric Hole-Transporting Materials for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Sanghyun Paek, Hiroyuki Kanda

A set of novel hole-transporting materials (HTMs) based on pi-extension through carbazole units was designed and synthesized via a facile synthetic procedure. The impact of isomeric structural linking on their optical, thermal, electrophysical, and photovo ...

AMER CHEMICAL SOC2020

D-pi-A-Type Triazatruxene-Based Dopant-Free Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Sanghyun Paek, Cristina Roldán Carmona, Hiroyuki Kanda, Cansu Igci, Hobeom Kim

Three donor-pi-bridge-acceptor (D-pi-A)-type organic small molecules coded CI-B1, CI-B2, and CI-B3 are designed, synthesized, and used as dopant-free hole transporting materials (HTMs) for perovskite solar cells (PSCs). The strong electron-donating triazat ...

WILEY-V C H VERLAG GMBH2020

Perovskite Solar Cells: 18% Efficiency Using Zn(II) and Cu(II) Octakis(diarylamine)phthalocyanines as Hole-Transporting Materials

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Valentin Ianis Emmanuel Queloz, Kyung Taek Cho, Marius Franckevicius, Sanghyun Paek, Hiroyuki Kanda

Metallophthalocyanines (MPcs) are currently emerging as alternative hole-transporting materials (HTMs) in perovskite solar cells (PSCs). However, the lack of systematic structure/photovoltaic properties investigations still hampers the rational design of M ...

2019

In-situ cross-linkable hole transporting triazatruxene monomers for optoelectronic devicestr

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Tom Theodorus Antonius Lummen, Aron Joel Huckaba

The invention discloses a polymerizable triazatruxene-based compound of formula (I), an optoelectronic and/or photoelectrochemical device comprising said compound of formula (I) as hole transporting material in hole transport layer under the form of a poly ...

2019

Efficiency vs. stability: dopant-free hole transporting materials towards stabilized perovskite solar cells

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Cansu Igci

In the last decade, perovskite solar cells have been considered a promising and burgeoning technology for solar energy conversion with a power conversion efficiency currently exceeding 24%. However, although perovskite solar cells have achieved high power ...

ROYAL SOC CHEMISTRY2019

Hole transporting organic molecules containing enamine groups for optoelectronic and photoelectrochemical devices

Kasparas Rakstys, Sanghyun Paek

The present invention relates to a compound of formula (I) based on enamine derivatives and used as organic hole conductors or hole transporting material in an optoelectronic or photoelectrochemical device. The present invention relates to the hole transpo ...

2018

Pyridination of hole transporting material in perovskite solar cells questions the long-term stability

Mohammad Khaja Nazeeruddin, Natalia Gasilova, Kasparas Rakstys, Sanghyun Paek

In this work, for the first time, reactive radical-cation species present in hole-transporting materials were shown to react with tert-butylpyridine additive, routinely used in hole transporting layer composition. As a result, new pyridinated products were ...

Royal Society of Chemistry2018

Dispiro-oxepine/thiapine derivatives for optoelectronic semiconductors

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Sanghyun Paek, Muhammad Sohail

The dispiro-oxepine/dispiro-thiapine derivatives for optoelectronic semiconductors is a compound based on a structure having a functionalized dispiro compound of formula (Ia) or (Ib) with the core unit being a seven-membered heterocycle oxepine or thiapine ...

2018

Solution processed organic light-emitting diodes using a triazatruxene crosslinkable hole transporting material

Mohammad Khaja Nazeeruddin, Kasparas Rakstys

2018

Diphenylamine-Substituted Carbazole-Based Hole Transporting Materials for Perovskite Solar Cells: Influence of Isomeric Derivatives

Mohammad Khaja Nazeeruddin, Paul Gratia, Kasparas Rakstys, Kyung Taek Cho, Sanghyun Paek

2018