Ferroelectric Ba0.75Sr0.25TiO3 tunable charge transfer in perovskite devices

Abstract Interfacial charge recombination is a main issue causing the efficiency loss of the perovskite solar cells (PSCs). Here, ferroelectric Ba0.75Sr0.25TiO3 (BST) is introduced as a polarization tunable layer to promote the interfacial charge transfer of the PSCs. The coexistence of ferroelectric polarization and charge carriers in BST is confirmed by density functional theory (DFT) calculations. Experimental characterization demonstrates the polarization reversal and the existence of domain in BST film. The BST film conductivity is tested as 2.98×10-4 S/cm, which is comparable to the TiO2 being used as the electron transporting layer (ETL) in PSCs. The calculations results prove that BST can be introduced into the PSCs and the interfacial charge transfer can be tuned by ferroelectric polarization. Thus, we fabricated the BST-based PSCs with a champion power conversion efficiency (PCE) of 19.05% after poling, which is higher for 4% than that without poling.

Download Full-text

Adsorption and Light Absorption Properties of 2-Anthroic Acid on Titania: a Density Functional Theory – Time-Dependent Density Functional Theory Study

MRS Advances ◽

10.1557/adv.2016.242 ◽

2016 ◽

Vol 1 (41) ◽

pp. 2795-2800

Author(s):

Sergei Manzhos ◽

Konstantinos Kotsis

Keyword(s):

Density Functional Theory ◽

Charge Transfer ◽

Light Absorption ◽

Density Functional ◽

Dye Sensitized Solar Cells ◽

Band Alignment ◽

Absorption Properties ◽

Functional Theory ◽

Interfacial Charge Transfer ◽

Interfacial Charge

ABSTRACTThe adsorption 2-anthroic acid on titania has been shown to result in an interfacial charge transfer band, which makes this a promising interface for dye-sensitized solar cells with direct injection. Here, we model the adsorption of 2-anthroic acid on a TiO2 nanocluster exhibiting a (101)-like interface and compute light absorption properties of this system using for the first time a hybrid functional. The band alignment and the formation of interfacial charge transfer bands proposed in previous experimental and lower-level computational works are confirmed.

Download Full-text

Improving interfacial charge transfer by multi-functional additive for high-performance carbon-based perovskite solar cells

Applied Physics Letters ◽

10.1063/5.0061869 ◽

2021 ◽

Vol 119 (15) ◽

pp. 151104

Author(s):

Yu Zou ◽

Wenjin Yu ◽

Zhenyu Tang ◽

Xiangdong Li ◽

Haoqing Guo ◽

...

Keyword(s):

Solar Cells ◽

Charge Transfer ◽

High Performance ◽

Perovskite Solar Cells ◽

Interfacial Charge Transfer ◽

Functional Additive ◽

Interfacial Charge ◽

Carbon Based

Download Full-text

Origins of genuine Ohmic van der Waals contact between indium and MoS2

npj 2D Materials and Applications ◽

10.1038/s41699-020-00191-z ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Bum-Kyu Kim ◽

Tae-Hyung Kim ◽

Dong-Hwan Choi ◽

Hanul Kim ◽

Kenji Watanabe ◽

...

Keyword(s):

Charge Transfer ◽

Contact Resistance ◽

Density Functional ◽

Van Der Waals ◽

Conduction Band Edge ◽

General Strategy ◽

Transition Metal Dichalcogenide ◽

Interfacial Charge Transfer ◽

Gap States ◽

Interfacial Charge

AbstractThe achievement of ultraclean Ohmic van der Waals (vdW) contacts at metal/transition-metal dichalcogenide (TMDC) interfaces would represent a critical step for the development of high-performance electronic and optoelectronic devices based on two-dimensional (2D) semiconductors. Herein, we report the fabrication of ultraclean vdW contacts between indium (In) and molybdenum disulfide (MoS2) and the clarification of the atomistic origins of its Ohmic-like transport properties. Atomically clean In/MoS2 vdW contacts are achieved by evaporating In with a relatively low thermal energy and subsequently cooling the substrate holder down to ~100 K by liquid nitrogen. We reveal that the high-quality In/MoS2 vdW contacts are characterized by a small interfacial charge transfer and the Ohmic-like transport based on the field-emission mechanism over a wide temperature range from 2.4 to 300 K. Accordingly, the contact resistance reaches ~600 Ω μm and ~1000 Ω μm at cryogenic temperatures for the few-layer and monolayer MoS2 cases, respectively. Density functional calculations show that the formation of large in-gap states due to the hybridization between In and MoS2 conduction band edge states is the microscopic origins of the Ohmic charge injection. We suggest that seeking a mechanism to generate strong density of in-gap states while maintaining the pristine contact geometry with marginal interfacial charge transfer could be a general strategy to simultaneously avoid Fermi-level pinning and minimize contact resistance for 2D vdW materials.

Download Full-text