IEC TS 62607-3-3:2020

Nanomanufacturing - Key control characteristics - Part 3-3: Luminescent nanomaterials - Determination of fluorescence lifetime of semiconductor quantum dots using time correlated single photon counting (TCSPC)

IEC 62607:2020, a Technical Specification, provides a method for determining the fluorescence lifetime of semiconductor quantum dots (QDs) using the time correlated single photon counting (TCSPC) technique. TCSPC is suitable for testing fluorescence lifetime in the range from picoseconds to nanoseconds. This document is only applicable to liquid samples that are stable dispersions of QDs. It is not applicable to solid samples.
This document includes:
– outlines of the experimental procedures,
– data processing, and
– case study.

General Information

• Status: Published
• Publication Date: 23-Sep-2020
• ICS: 07.030 - Physics. Chemistry
• ICS: 07.120 - Nanotechnologies
• Technical Committee: TC 113 - Nanotechnology for electrotechnical products and systems
• Drafting Committee: PT 62607-3-3 - TC 113/PT 62607-3-3
• Current Stage: PPUB - Publication issued
• Start Date: 24-Sep-2020
• Completion Date: 16-Oct-2020

Overview

IEC TS 62607-3-3:2020 defines a standardized method for measuring the fluorescence lifetime of semiconductor quantum dots (QDs) using time correlated single photon counting (TCSPC). This Technical Specification applies to liquid samples that are stable dispersions of QDs (not solid samples) and covers the full workflow: experimental procedures, data processing and a case study. TCSPC in this standard is suitable for fluorescence lifetime measurements in the picoseconds to nanoseconds range.

Key topics and requirements

• Test principle: Use of TCSPC to build a histogram of photon arrival times after repetitive pulsed excitation to derive fluorescence decay curves.
• Sample scope: Only liquid, stable QD dispersions; solid-state samples are excluded.
• Measurement equipment: TCSPC fluorescence spectrometer with appropriate pulsed laser excitation and single-photon detectors; instrumentation must support high repetition-rate excitation to accumulate photon statistics.
• Measurement procedure:
  • Instrument preparation and alignment
  • Fluorescence lifetime decay curve acquisition
  • Instrumental response function (IRF) measurement
  • Data fitting and analysis (decay deconvolution, lifetime extraction)
• Data handling: Procedures for processing decay curves, fitting models (single/multi-exponential where applicable), and reporting results.
• Reporting and uncertainty: Required test report elements and identification of major uncertainty sources for traceable lifetime values.
• Supporting material: Informative annexes including a practical case study and examples of laser excitation sources used in TCSPC.

Applications and who uses it

IEC TS 62607-3-3 is important for organizations and professionals working with luminescent nanomaterials and semiconductor quantum dots, including:

• Nanomaterials manufacturers performing quality control and process validation
• R&D laboratories characterizing optical properties of QDs for LEDs, displays, lasers, and bioimaging
• Metrology and standards laboratories establishing traceable fluorescence lifetime measurements
• Instrument manufacturers and service labs calibrating TCSPC systems

Measuring fluorescence lifetime provides environment- and structure-sensitive information that is largely independent of concentration or excitation intensity, making it valuable for evaluating solvent effects, quenching, molecular interactions, and kinetic processes in QD dispersions.

Related standards

• IEC 62607 series - Nanomanufacturing – Key control characteristics (other parts)
• ISO 3696 - Water for analytical laboratory use
• ISO 385, ISO 648, ISO 1042 - Laboratory glassware standards cited for sample preparation

Keywords: IEC TS 62607-3-3, fluorescence lifetime, TCSPC, quantum dots, luminescent nanomaterials, semiconductor QDs, time correlated single photon counting, IRF, nanomanufacturing

Standards Content (Sample)

IEC TS 62607-3-3 ®
Edition 1.0 2020-09
TECHNICAL
SPECIFICATION
colour
inside
Nanomanufacturing – Key control characteristics –
Part 3-3: Luminescent nanomaterials – Determination of fluorescence lifetime of
semiconductor quantum dots using time correlated single photon counting
(TCSPC)
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IEC TS 62607-3-3 ®
Edition 1.0 2020-09
TECHNICAL
SPECIFICATION
colour
inside
Nanomanufacturing – Key control characteristics –

Part 3-3: Luminescent nanomaterials – Determination of fluorescence lifetime of

semiconductor quantum dots using time correlated single photon counting

(TCSPC)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 07.030, ICS 07.120 ISBN 978-2-8322-8881-8

– 2 – IEC TS 62607-3-3:2020  IEC 2020
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 7
4 Test principle . 7
5 Sample preparation . 8
6 Measurement . 8
6.1 TCSPC fluorescence spectrometer . 8
6.2 Measurement procedure . 8
6.2.1 Instrument preparation . 8
6.2.2 Fluorescence lifetime decay curve measurement . 9
6.2.3 IRF measurement . 10
6.2.4 Data analysis . 10
7 Test reports . 10
8 Uncertainty source. 10
Annex A (informative) Case study for determining fluorescence lifetime of
semiconductor quantum dots . 11
A.1 General . 11
A.2 QDs sample . 11
A.3 Instruments . 11
A.4 Measurement conditions for TCSPC . 11
A.5 Procedures for measurement . 11
A.5.1 Instrument preparation . 11
A.5.2 Fluorescence lifetime decay curve measurement . 11
A.5.3 IRF measurement . 12
A.6 Results of fluorescence lifetime decay curve . 12
A.7 Data analysis . 13
Annex B (informative) Typical laser input excitation sources used in TCSPC . 14
Bibliography . 15

Figure 1 – The schematic of start-stop times in time-resolved fluorescence
measurement with TCSPC . 7
Figure 2 – The working schematic of TCSPC fluorescence spectrometer . 8
Figure 3 – Examples for typical single exponential decay curves obtained in different
measurement ranges . 9
Figure A.1 – Typical fluorescence lifetime decay curve . 12
Figure A.2 – Fitting result curve and IRF curve . 13

Table B.1 – Typical laser input excitation sources used in TCSPC . 14
Table B.2 – Fluorescence lifetime of commonly used semiconductor QDs . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NANOMANUFACTURING – KEY CONTROL CHARACTERISTICS –

Part 3-3: Luminescent nanomaterials – Determination of fluorescence
lifetime of semiconductor quantum dots using time correlated single
photon counting (TCSPC)
FOREWORD
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Technical Specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62607-3-3, which is a Technical Specification, has been prepared by IEC technical
committee 113: Nanotechnology standardization for electrotechnical products and systems.

– 4 – IEC TS 62607-3-3:2020  IEC 2020
The text of this Technical Specification is based on the following documents:
Enquiry draft Report on voting
113/490/DTS 113/529/RVDTS
Full information on the voting for the approval of this Technical Specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62607 series, published under the general title Nanomanufacturing –
Key control characteristics, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
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• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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INTRODUCTION
Fluorescence lifetime is considered as the average time that luminescent materials spend in
the excited state before emitting a photon and returning to the ground state. Fluorescence
lifetime can vary widely from picoseconds to hundreds of nanoseconds, even to microseconds
or milliseconds, depending on the type of luminescent nanomaterials.
Fluorescence lifetime is an important property of luminescent materials. Fluorescence lifetime
does not depend on fluorophore concentration, absorption by the sample, thickness of the
sample, method of measurement, fluorescence intensity, photo-bleaching, and/or excitation
intensity. It is affected by external factors, such as temperature, polarity of solvent, and the
presence of fluorescence quenchers. Fluorescence lifetime is sensitive to internal factors that
are dependent on fluorophore structure.
The possible applications of measuring fluorescence lifetime include the following:
a) determine the environment that the sample molecules inhabit, e.g. viscosity, pH value,
temperature, polarity, and solvation, etc.;
b) uncover the size and shape of the sample molecules, and the distances between different
parts of the molecules;
c) learn about the contributions of each component in a mixture of sample molecules, through
time-resolved spectra of overlapping emissions;
d) reveal the molecular interactions;
e) obtain the kinetic and dynamic rates.
Time-correlated single photon counting (TCSPC) is a widely used, sensitive, reproducible and
precise technique to measure the photon arrival time in applications characterized by a strong
demand in terms of temporal resolution such as fluorescence lifetime spectroscopy and imaging,
photon migration and time of flight measurements.

– 6 – IEC TS 62607-3-3:2020  IEC 2020
NANOMANUFACTURING – KEY CONTROL CHARACTERISTICS –

Part 3-3: Luminescent nanomaterials – Determination of fluorescence
lifetime of semiconductor quantum dots using time correlated single
photon counting (TCSPC)
1 Scope
This part of IEC 62607, which is a Technical Specification, provides a method for determining
the fluorescence lifetime of semiconductor quantum dots (QDs) using the time correlated single
photon counting (TCSPC) technique. TCSPC is suitable for testing fluorescence lifetime in the
range from picoseconds to nanoseconds. This document is only applicable to liquid samples
that are stable dispersions of QDs. It is not applicable to solid samples.
This document includes:
– outlines of the experimental procedures,
– data processing, and
– case study.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO 3696, Water for analytical laboratory use – Specification and test methods
ISO 385, Laboratory glassware – Burettes
ISO 648, Laboratory glassware – Single-volume pipettes
ISO 1042, Laboratory glassware – One-mark volumetric flasks
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
time correlated single photon counting
TCSPC
technique based on detecting single photons of periodical light signal, measuring the detection
times, and building up the distribution
...