LuQY Pro

The Absolute Luminescence Quantum Yield System

When developing opto-electronic devices, such as LEDs or solar cells, it is essential to improve their radiative efficiency. This requires precise techniques to determine the luminescence quantum yield. The LuQY Pro is an easy-to-use, non-invasive and versatile system with unparalleled compactness to swiftly quantify absolute electro- and photoluminescence photon fluxes of thin film absorbers, layer stacks or complete devices under various operating conditions.

System & Layout

  • Swift quantification of Absolute Photon Fluxes from electro- and photoluminescence (EL & PL) of semiconductor thin films & devices

  • USB-“Plug & Play”: the included software records emission spectra & directly calculates EL/PL Quantum Yield & implied Voc

  • Small & Portable Layout allows flexible usage e.g. in gloveboxes

One-Click Measurements

  • Absolute number of photons from steady-state EL/PL spectra (550–1050 nm)

  • Automated, continuously adjustable laser intensity from 0.001-10 “Suns”
  • Current/voltage biasing and sensing via integrated source & measure unit (SMU)
  • EL/PLQY sensitivity range: 1E-4 %


  • Absolute photon flux measurement
    Records single or multiple EL/PL spectra for pre-set laser intensity, voltage & current bias

  • Immediate calculation of EL/PLQY & iVoc
  • Automated measurement sweeps
    Varies laser intensity, bias voltage & current and determines absolute PL/EL spectra, EL/PLQY and iVoc at each operating point


Quality Assessment

Quality assessment for rapid Process Control after each fabrication step or for Accelerated Material and Process Parameter Screenings.

Transient Effects

Fast Acquisition resolves Shifts in Emission Spectrum & Intensity as well as EL/PLQY and iVoc on timescales from 10 ms to several hours.

Resolve Bulk & Interface Recombination

Quantifying Bulk and Interface Recombination Losses in semiconductor thin films, layer stacks or complete devices such as solar cells or LEDs. Examples in academic publications can be found in [1-6].

Efficiency Potentials & Loss Mechanisms

In-depth analysis of efficiency potentials and loss mechanisms in semiconductor thin films, layer stacks or complete devices, e.g. by determining Ideality Factors and Pseudo-JV Curves from Intensity and/or Bias-Voltage Dependent EL/PLQY & iVoc. Also see [7-9]

Technical Specifications

Current-voltage source and measure unit (SMU) max. ratings

+/-10 V, +/-150 mA

Max. sample dimensions (L x W, unrestricted height)

30 x 30 mm

Max. no. of contactable subcells on sample by integrated relais box

6 subcells

Photoexcitation intensity (continuously adjustable)

0.001 – 10 “Suns”

Photoexcitation wavelength

532 nm

Photoexcitation spot size (interchangeable)

0.1 cm² / 1 cm²

Spectral detection range

550 – 1050 nm

Quantum yield sensitivity range

10-4 – 100%

Corresponding min. resolvable iVoc for 1.6 eV absorber band gap

1.0 V

Spectrometer integration time

1 ms – 65 s

Dimensions (L x W x H)

220 x 275 x 120 mm³


4.7 kg


1x DC, 1x USB 3.0


Amran Al-Ashouri
Amran Al-Ashouri
Aboma Merdasa
Aboma Merdasa
Steve Albrecht
Steve Albrecht
Thomas Unold
Thomas Unold
José A. Márquez
José A. Márquez
Lukas Kegelmann
Lukas Kegelmann

Advisory Board

Eva Unger
Eva Unger
Christian M. Wolff
Christian M. Wolff
Pietro Caprioglio
Pietro Caprioglio
Martin Stolterfoht
Martin Stolterfoht
Dieter Neher
Dieter Neher

Our team with our excellent advisory board is a multi-disciplinary group of researchers from the Helmholtz-Zentrum Berlin, the Potsdam University, the École Polytechnique Fédérale de Lausanne and the University of Oxford (PIs, Postdocs & PhD students). In this unique constellation, we combine exceptional expertise in:

  • Perovskite based tandem solar cells
  • Advanced spectroscopy on perovskite films and devices
  • Absolute photo- & electroluminescence measurements (recombination loss analysis)

We have been frequently using and promoting absolute luminescence measurements throughout recent years. The method enormousely helped us to develop efficient solar cell materials and greatly accelerated the device development. In fact, absolute luminescence measurements were the key characterization technique enabling us to realize a world record certified perovskite/silicon tandem solar cell efficiency of 29.15% in January 2020 (also see Al-Ashouri et al., Science 2020)


References marked with ‡ indicate publications with contributions from members of our team.

Resolving bulk and interface recombination losses from absolute PL:

[1]‡ Unold et al., Advanced Characterization Techniques for Thin Film Solar Cells, Chapter 7: Photoluminescence Analysis of Thin-Film Solar Cells, Wiley, 2011, ISBN: 9783527410033

[2]‡ Al-Ashouri et al., Energy Environ. Sci., 2019, 12, 3356-3369

[3]‡ Kegelmann et al., ACS Appl. Mater. Interfaces, 2019, 11, 9, 9172-9181

[4]‡ Stolterfoht et al., Energy Environ. Sci., 2019, 12, 2778-2788

[5]‡ Liu et al., ACS Energy Lett., 2019, 4, 1, 110-117

[6]‡ Kirchartz et al., Adv. Energy Mater., 2020, Early View 1904134.

Ideality factor and pseudo-JV curves from light-intensity dependent absolute PL:

[7]‡ Caprioglio et al., Adv. Energy Mater., 2019, 9, 33, 110-117

[8]‡ Stolterfoht et al., Adv. Mater., 2020, DOI: 10.1002/adma.202000080

[9] Chris Dreessen et al., Journal of Luminescence, 2020, 222, 117106


Dr. Lukas Kegelmann