IMPS/IMVS to evaluate carrier transport time, recombination rates and other time scales

Intensity Modulated Photocurrent/Photovoltage Spectroscopy.


The IMPS/IMVS instrument allows to perform sample examination that is complementary to static photovoltage/photocurrent measurements. Monochromatic LED with modulated light intensity of sinusoidal waveform in wide range of frequencies enables to investigate many kinetic quantities: diffusion parameters, time scales of the sample: carrier transport time, recombination rates and many others. In case of photoelectrochemical samples immersed in an electrolyte, the sample may be illuminated on both sides: through the electrolyte, to investigate electrolyte-sample surface interface, or through the rear optical window for substrate-sample interface examination. The sample setup is placed in the Sample Chamber that screens ambient light and external EM fields.

Quantities measured by the instrument:

  • Minority carriers lifetime (recombination time),
  • Carrier transport time through the sample,
  • Rate of the charge transfer through the interfaces,
  • Diffusion constant,
  • Diffusion length for a given sample thickness,
  • Sample thickness for a given diffusion length,
  • Other kinetic quantities.



IMPS/IMVS modules

The instrument consists of:

Click to enlarge


 LED Revolver

  • 10 LED slots,
  • Default LED set: 365 nm, 385 nm, 405 nm, 450 nm, 520 nm, 590 nm, 630 nm, 740 nm, 840 nm, white (3000 K),
  • Custom LED selection available,
  • Typical electric power of LEDs: 3W,
  • Light intensity modulation: square, saw or sinusoidal waveform with adjustable amplitude and bias light intensity,
  • Light modulation frequency range: 1 µHz ÷ 10 kHz,


  • Maximum sampling rate: 1 kSample/s,
  • Connection with PC: via USB 2.0,


  • Bias potential range: -5 V ÷ 5 V,
  • Current ranges: 10 nA, 100 nA, 1 µA, 10 µA, 100 µA, 1 mA, 10 mA,
  • Current resolution: from 1 pA to 100 nA (range dependent),

Electrochemical cuvette

  • Adapted for transparent and opaque samples,
  • PTFE container for electrolyte,
  • Reference electrode: Ag/AgCl,
  • Counter electrode: Pt.

Sample Chamber Interior

Click to enlarge

exemplary results

The measurement results shown below are obtained for nanocrystaline anatase on ITO foil in KNO3 electrolyte.

Photocurrent spectrum.

Warning: the current sign convention assumed is normal in contrast to potentiostatic measurements (adopted by all the potentiostats in the world) where the IUPAC (inverse sign) convention is used.
Click to enlarge

Nyquist (Argand) plot in 3d showing real and imaginary part of photocurrent as a function of light modulation frequencies.
Click to enlarge

Amplitudes of higher harmonics.
Click to enlarge


ACCESSORIES The following accessories are compatible with the product
Light Calibrator
LEAVE YOUR CONTACT INFORMATION - We will respond within 48h

    I agree that provided personal information will be processed by Instytut Fotonowy Sp. z o.o. only for the purpose of business offer for the relevant product.

    CONTACT US - We will address all your questions + 48 733 003 380 office@fotonowy.pl

    Similar products