Perspectives for CdSe/CdS spherical quantum wells as rapid-response nano-scintillators

Area of Science:

• Materials Science
• Nanotechnology
• Quantum Physics

Background:

• Spherical quantum wells (SQWs) are crucial for advanced scintillator applications.
• Understanding the influence of shell thickness on nanoscintillator performance is vital for optimizing their use.
• CdS/CdSe/CdS heterostructures offer unique optoelectronic properties for energy detection.

Purpose of the Study:

• To investigate the effect of shell thickness on the time response of CdS/CdSe/CdS SQW nanoscintillators.
• To analyze spectral and timing properties under varying excitation intensities (optical and X-ray).
• To elucidate the mechanisms behind luminescence and energy relaxation in these nanostructures.

Main Methods:

• Comparative analysis of spectral and timing properties under low and intense optical excitation.
• Pulsed X-ray excitation to study scintillation decay times.
• Two-step simulation of energy relaxation processes within the SQWs.

Main Results:

• Defect-induced delayed luminescence observed in large-sized SQWs.
• Evidence of multiexciton generation under pulsed X-ray excitation, similar to intense optical excitation.
• Shell thickness showed minimal impact on the fast scintillation component fraction.
• Increased Auger quenching in large SQWs counterbalances high excitation numbers, reducing timing performance.

Conclusions:

• The timing performance of CdS/CdSe/CdS SQW nanoscintillators is complex and influenced by size-dependent phenomena.
• While large SQWs can host high excitation numbers, efficient energy transfer and timing are hindered by Auger quenching.
• Optimizing shell thickness and size is critical for developing high-performance nanoscintillators for X-ray detection.