Intensity modulated photocurrent and photovoltage spectroscopy system

Intensity modulated photocurrent and photovoltage spectroscopy systemAllow for sample inspection complementary to static photovoltaic/photocurrent measurements. Monochrome LED has a modulated light intensity with a sine waveform over a wide frequency range, which can be used to study many dynamic parameters such as diffusion parameters, sample time scale, carrier transport time, recombination rate, etc. If the photoelectrochemical sample is immersed in the electrolyte, the sample can be irradiated from both sides: through the electrolyte to study the electrolyte sample surface interface, or through the rear optical window for substrate sample interface inspection. Place the sample in the sample chamber to shield it from ambient light and external electromagnetic fields.

Intensity modulated photocurrent and photovoltage spectroscopy systemQuantity measured:

• Minority carrier lifespan (recombination time),

• The transport time of charge carriers through the sample,

• Through the charge transfer rate of the interface,

• Diffusion constant/

• Given the diffusion length of the sample thickness,

• Given the thickness of the sample with a given diffusion length,

• Other kinetic quantities.

IMPS/IMVS module

The instrument includes:

• LED converter light source/

• Electrochemical workstation for measuring photocurrent and open circuit potential (OCP),

• Electrochemical shielding box, used to shield external electromagnetic fields and ambient light,

• Electrochemical colorimetric dish with Pt and Ag/AgCl electrodes.

Specifications

LED converter

• 10 LED slots,

• 默认 LED 设置： 365 nm、385 nm、405 nm、450 nm、520 nm、590 nm、630 nm、740 nm、840 nm、 白色 （3000 K）、

• Provide customized LED options,

• Typical power of LED: 3W,

• Light intensity modulation: square wave, sawtooth wave or sine wave, with adjustable amplitude and bias light intensity,

• Optical modulation frequency range: 1 μ Hz ÷ 10 kHz,

controller

• Maximum sampling rate: 1 kSample/s,

• Connected to PC: via USB 2.0,

potentiostat

• Bias potential range: -5 V ÷ 5 V,

• Current range: 10 nA, 100 nA, 1 μ A, 10 μ A, 100 μ A, 1 mA, 10 mA

• Current resolution: from 1 pA to 100 nA (depending on the range),

Electrochemical colorimetric dish

• Suitable for transparent and opaque samples,

• PTFE container for electrolyte,

• Reference electrode: Ag/AgCl,

• Electrode: Pt

Inside the electrochemical shielding box

measurement results

The measurement results shown in the following figure were obtained for nanocrystalline rutile on ITO foil in KNO3 electrolyte.

Photoelectric current spectrum.

Tip: Compared to the constant potential measurement using the IUPAC (inverse symbol) convention (adopted by all potentiometers in the world), the current assumed symbol convention is normal.

The 3D Nyquist (Argand) plot shows the functional relationship between the real and imaginary parts of photocurrent and the modulation frequency of light.

The amplitude of high-order harmonics.