Hybrid 0D Antimony Halides as Air-Stable Luminophores for High-Spatial-Resolution Remote Thermography.

Viktoriia Morad,Bogdan M Benin,Ivan Shorubalko,Yevhen Shynkarenko,Sergii Yakunin,Simon C Boehme,Maksym V Kovalenko,Matthias J Grotevent

doi:10.1002/adma.202007355

Abstract

Luminescent organic-inorganic low-dimensional ns2 metal halides are of rising interest as thermographic phosphors. The intrinsic nature of the excitonic self-trapping provides for reliable temperature sensing due to the existence of a temperature range, typically 50-100 K wide, in which the luminescence lifetimes (and quantum yields) are steeply temperature-dependent. This sensitivity range can be adjusted from cryogenic temperatures to above room temperature by structural engineering, thus enabling diverse thermometric and thermographic applications ranging from protein crystallography to diagnostics in microelectronics. Owing to the stable oxidation state of Sb3+ , Sb(III)-based halides are far more attractive than all major non-heavy-metal alternatives (Sn-, Ge-, Bi-based halides). In this work, the relationship between the luminescence characteristics and crystal structure and microstructure of TPP2 SbBr5 (TPP = tetraphenylphosphonium) is established, and then its potential is showcased as environmentally stable and robust phosphor for remote thermography. The material is easily processable into thin films, which is highly beneficial for high-spatial-resolution remote thermography. In particular, a compelling combination of high spatial resolution (1µm) and high thermometric precision (high specific sensitivities of 0.03-0.04 K-1 ) is demonstrated by fluorescence-lifetime imaging of a heated resistive pattern on a flat substrate, covered with a solution-spun film of TPP2 SbBr5 .

Highlights

The rapid technological advances of the last century have resulted in new chalinterest as thermographic phosphors
Remote, contactless, and realof a temperature range, typically 50–100 K wide, in which the luminescence lifetimes are steeply temperature-dependent. This sensitivity range can be adjusted from cryogenic temperatures to above room temperature by structural engineering, enabling diverse thermometric and time micro- and nanoscale temperature mapping is of great demand in cell imaging, micro- and nanofluidics, and integrated circuit design,[1,2,3,4,5,6,7,8,9,10,11] in which these stringent requirements necessitate thermographic applications ranging from protein crystallography to diagnostics the use of optical methods
The material is processable into thin films, which is highly beneficial for high-spatial-resolution remote thermography

Summary

Introduction

The rapid technological advances of the last century have resulted in new chalinterest as thermographic phosphors. While these halides are typically discussed in the context of utility-scale applications such as solid-state lighting,[48] we have recently demonstrated their use as thermoluminophores in remote thermometry and millimeter-scale thermography owing to the steep temperature dependence of their luminescence decay rates.[49] The temperature distribution of a surface can be mapped by conducting fluorescence-lifetime imaging (FLIM, Figure 1a).

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Conclusion