Fourier Transform Photocurrent Spectroscopy (FTPS) / Highly Sensitive External Quantum Efficiency (HS-EQE)

FTPS (CTS / Trap State)

The Most Sensitive Photocurrent and EQE / IPCE System in the World.

　　In semiconductor devices, imperfect crystallinity often causes defects or trap states in the forbidden bandgap. These greatly affect the overall optical and electrical performance of the device. Since the absorption coefficient in the bandgap is extremely low, the generated photocurrent signal is also extremely weak. Therefore, a highly sensitive detection system is required.

　　Enlitech‘s FTPS is a highly sensitive photocurrent and external quantum efficiency (HS-EQE) spectroscopy system. It utilizes Fourier Transform Signal Processing technology to enhance and break through the photocurrent signal detection limits. The lowest EQE level can be as low as 10-5% (7 orders)*. FTPS can be applied to detect the tail states of perovskite solar cells and the charge transfer state of organic solar cells, which are key to improving Voc loss mechanisms. Another common application is Urbach Energy measurement.

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Features

Direct spectroscopy evidence for trap states, defect states or charge transfer states.
Wavelength range: 0.7-2 eV, 600-1800nm.
Turn-key solution; generate reliable spectral data after installation. Time-saving and cost-effective (at least 1-year and 20k USD).
Complete the training course, which includes operational and fundamental background training.
Proven by over 50 SCI journal papers.
Not just data acquisition, but also energy level fitting! We provide CTS and Urbach Energy level fitting software.

System Design

Specification

10-5% (7 orders)* the detection dynamic of FTPS system can be 7 orders, but the lowest EQE level is determined by DUT's thermal noise itself.

Model	FTPS (PECT-600)
Wavelength Range	0.7-2 eV, 600-1800nm
Dynamic Range	≥ 7 orders ≥120dB; and can be extended to 140dB (option)
Repeatability	>99 % (under AM1.5G)
Software	Charge Transfer Energy Fitting, Urbach Energy Calculation
Equipment dimension	550(L)510(W)355.3mm(H)

Application

Voc Loss Mechanism and Charge Transfer State Study on 16% Efficiency Organic Photovoltaic Cells

　　In 2019, Dr. JH Hou’s group from ICCAS used Enlitech’s PECT-600 and REPS systems to study the mechanism of increased open-circuit voltage in 16% efficiency organic solar cells with a chlorinated acceptor system. The authors report a chlorinated non-fullerene acceptor, which exhibits an extended NIR optical absorption and contributes to the short-circuit photocurrent (from the EQE spectrum measured by Enlitech’s QE-R system).

　　This system also reveals a higher Voc, which was explored by highly sensitive PV-EQE and EL-EQE techniques (FTPS PECT-600 and REPS systems). The main reason for the increased open-circuit voltage is due to the significant reduction in non-radiative decay loss (0.206 eV). Therefore, this chlorinated acceptor can simultaneously increase the short-circuit current density and the open-circuit voltage. The excellent result is published in Nature Communications.

Reference:

　　Over 16% efficiency organic photovoltaic cells enabled by a chlorinated acceptor with increased open-circuit voltages. Yong Cui, Huifeng Yao, Jianqi Zhang, Tao Zhang, Yuming Wang, Ling Hong, Kaihu Xian, Bowei Xu, Shaoqing Zhang, Jing Peng, Zhixiang Wei, Feng Gao & Jianhui Hou Nature Communications volume 10, 2515 (2019)

Proof

　　Organic PV INFO reported on February 18, 2021, that understanding and minimizing performance losses are crucial for achieving higher OPV efficiencies. The FTPS system of PECT-600 is helping researchers understand the details about the Voc loss mechanisms. Link

~18% Organic Solar Cell

Enlitech’s Voc loss Analysis tool was used to develop new materials for organic photovoltaic cells, which achieved nearly 18% efficiency.

~17% Organic Solar Cell

Enlitech’s quantum efficiency measurement system was used for Voc loss calculation, and organic solar cells with nearly 17% efficiency were developed.

Perovskite Solar Cell (Voc=1.16V)

Enlitech’s Voc loss analysis technique provides proof of suppressing non-radiative recombination loss with Lewis base. The Voc of perovskite solar cells improved from 1.10 V to 1.16 V.

Installation Gallery

FTPS Fourier Transform Photocurrent Spectroscopy 傅里葉轉換光電流譜