IntroductionPhotoVoltaic (PV) Technology is the driving force for the renewable energy with efficiency being the number one parameter to be optimized in order to achive grid parity and allow wider adoption of this “green” energy production approach. PM-QE is an integrated tool for the in-depth characterization of PV devices that provides direct determination of device spectral response (SR, A/W), external quantum efficiency (EQE/IPCE, %) and internal quantum efficiency (IQE, %). The light path in PM-QE is through optical fibers instead of free-space optics that allow for flawlessly operation over long periods without any need of re-alignment and moving parts and without any effect from the environmental light.
The standard configuration of PM-QE system consists of a 300-1100nm light source with 1/4m monochromator. A motorized 6-positions filter wheel for high order sorting is also included. The photocurrent measurements are performed through lock-in amplifier with a digital controlled chopper. A software controlled light source, consisting of LEDs, is used for biasing measurements in the case of tandem cells, while a well-characterized monitoring photodiode is used as a reference. For the IQE measurements two integration spheres along with a miniaturized spectrometer are used for the determination of the Reflectance and/or Transmittance. The spectrometer is also used for the calibration and output spectra bandwidth determination of the monochromator. Furthermore temperature-controlled base for the sample under characterization and an external voltage bias source (optional) are available.
|PM-QE typical Configuration diagram||PM-QE installed|
PM-Monitor® is the software that fully controls the PM-QE tool and has been developed on the LabView platform. PM-Monitor® is used for the tool control and processing of the electronic and spectral measurements and offers unique capabilities for a wide range of applications and versatility. PM-Monitor® has been designed in such a way to guide the user to perform the measurements through a sequence of individual steps allowing that way the straightforward operation of the tool from personnel without any special skills on optics/electronics.
PM-Monitor® consists of two modules: a) EQE-module for the measurement of External Quantum Efficiency of the sample and for the control of all sub-modules such as biasing, temperature etc. b) IQE-module that measures the Reflectance and/or Transmittance of the sample and calculate the Internal Quantum Efficiency. The IQE-module is also used for the definition of the monochromator’s output bandwidth, without the need of laser sources and special calibration procedures.
Thanks to the carefully designed architecture and the components employed, the PM-QE: