Room temperature synthesis of stable silica-coated CsPbBr₃ quantum dots for amplified spontaneous emission

Abstract

All-inorganic cesium lead bromide ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> ) perovskite quantum dots (QDs) with excellent optical properties have been regarded as good gain materials for amplified spontaneous emission (ASE). However, the poor stability as the results of the high sensitivity to heat and moisture limits their further applications. Here, we report a facile one-pot approach to synthesize <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:mo>@</mml:mo> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs at room temperature. Due to the effective defects passivation using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m3"> <mml:mrow> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> , as-prepared <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m4"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:mo>@</mml:mo> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs present an enhanced photoluminescence quantum yield (PLQY) and chemical stability. The PLQY of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m5"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:mo>@</mml:mo> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs reaches 71.6% which is higher than 46% in pure <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m6"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs. The PL intensity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m7"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:mo>@</mml:mo> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs maintains 84% while remaining 24% in pure <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m8"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> after 80 min heating at 60°C. The ASE performance of the films is also studied under a two-photon-pumped laser. Compared with the films using pure <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m9"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs, those with as-prepared <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m10"> <mml:mrow> <mml:msub> <mml:mi>CsPbBr</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:mo>@</mml:mo> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> QDs exhibit a reduced threshold of ASE. The work suggests that room-temperature-synthesized <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m11"> <mml:mrow> <mml:msub> <mml:mi>SiO</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> -coated perovskites QDs are promising candidates for laser devices.

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